Stereoselective mannich-type reaction of an acyclic ketimine with a substituted chlorotitanium enolate: Efficient approach to D-erythro-α- trifluoromethyl-β-hydroxyaspartic units

Journal of Organic Chemistry

Volumn 64, Issue 23, 1999, Pages 8731-8735

  Bravo, Pierfrancesco ^a   Fustero, Santos ^b   Guidetti, Maurizia ^c   Volonterio, Alessandro ^c   Zanda, Matteo ^c,d  

^a CNR   (Italy)

^b UNIVERSITY OF VALENCIA   (Spain)

^c POLITECNICO DI MILANO   (Italy)

^d UNIVERSITÉ DE STRASBOURG   (France)

Author keywords

[No Author keywords available]

Indexed keywords

(2 BENZOYL 3 HYDROXY 1 HYDROXYMETHYL 1 TRIFLUOROMETHYLPROPYL)CARBAMIC ACID BENZYL ESTER; 2 BENZYLOXYCARBONYLIMINO 3,3,3 TRIFLUOROPROPIONIC ACID; ANTITHROMBOCYTIC AGENT; UNCLASSIFIED DRUG;

ARTICLE; CHEMICAL REACTION; CONFORMATIONAL TRANSITION; DRUG CONFORMATION; DRUG SYNTHESIS; STEREOCHEMISTRY; STRUCTURE ACTIVITY RELATION; THROMBOCYTE AGGREGATION INHIBITION;

EID: 0033550292     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo9909397     Document Type: Article

References (68)

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2. See, for example: McDowell, R. S.; Gadek, T. R. J. Am. Chem. Soc. 1992, 114, 9245.
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4. (a) Fluorine-containing Amino Acids: Synthesis and Properties; Kukhar, V. P., Soloshonok, V. A., Eds.; Wiley: Chichester, 1994.
5. (b) Koksch, B.; Sewald, N.; Jakubke, H.-D.; Burger, K. In Biomedical Frontiers of Fluorine Chemistry; Ojima, I., McCarthy, J. R., Welch, J. T., Eds.; American Chemical Society: Washington, DC, 1996; pp 42-58.
6. It is worth noting that the D-eryrtro-α-Tfm-β-hydroxyaspartic unit A can be also envisaged as a suitable precursor of the polar head of the 2-Tfm-analogue of natural sphingosine, the structural unit common to most natural sphingolipids. For a review, see: Koskinen, P. M.; Koskinen, A. M. P. Synthesis 1998, 1075. Efforts directed toward the total synthesis of D-erythro-2-Tfm-sphingosine are presently in progress.
7. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
8. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
9. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
10. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
11. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
12. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
13. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
14. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
15. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
16. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
17. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
18. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
19. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
20. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
21. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
22. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
23. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
24. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
25. For some reviews: (a) Bloch, R. Chem. Rev. (Washington, D.C.) 1998, 98, 1407. (b) Enders, D.; Reinhold, U. Tetrahedron: Asymmetry 1997, 8, 1895. To our knowledge, the few existing examples are limited to stereoselective aldol reactions of acyclic N-sulfinylketimines with enolates of acetate: (c) Davis, F. A.; Reddy, R. T.; Reddy, R. E. J. Org. Chem. 1992, 57, 6387. (d) Tang, T. P.; Ellman, J. A. J. Org. Chem. 1999, 64, 12. For leading references on asymmetric condensations of enolates with aldimines, see: (e) Abrahams, I.; Motevalli, M.; Robinson, A. J.; Wyatt, P. B. Tetrahedron 1994, 50, 12755. (f) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron Lett. 1993, 34, 6921. (g) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Ponzini, F.; Raimondi, L. Tetrahedron 1994, 50, 2939. (h) Annunziata, R.; Benaglia, M.; Chiovato, A.; Cinquini, M.; Cozzi, F. Tetrahedron 1995, 51, 10025. (i) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 5821. (j) Annunziata, R.; Benaglia, M.; Cinquini, M.; Cozzi, F.; Raimondi, L. Tetrahedron 1994, 50, 9471. (k) Boger, D. L.; Honda, T. Tetrahedron Lett. 1993, 34, 1567. (l) Gennari, C.; Vulpetti, A.; Pain, G. Tetrahedron 1997, 53, 5909. (m) Vaccaro, W. D.; Sher, R.; Davis, H. R., Jr. Bioorg. Med. Chem. Lett. 1998, 8, 35. (n) Fujisawa, T.; Ichikawa, M.; Ukaji, Y.; Shimizu, M. Tetrahedron Lett. 1993, 34, 1307. (o) Evans, D. A.; Morrissey, M. M.; Dorow, R. L. J. Am. Chem. Soc. 1985, 107, 4346. (p) van der Steen, F. H.; Kleijn, H.; Britovsek, G. J. P.; Jastrzebski, J. T. B. H.; van Koten, G. J. Org. Chem. 1992, 57, 3906. (q) Corey, E. J.; Decicco, C. P.; Newbold, R. C. Tetrahedron Lett. 1991, 32, 5287. (r) Gennari, C.; Venturini, I.; Gislon, G.; Schimperna, G. Tetrahedron Lett. 1987, 28, 227. (s) Hart, D. J.; Lee, C.-S. J. Am. Chem. Soc. 1986, 108, 6054.
26. (a) Bravo, P.; Crucianelli, M.; Vergani, B.; Zanda, M. Tetrahedron Lett. 1998, 39, 7771.
27. (b) Ishii, A.; Miyamoto, F.; Higashiyama, K.; Mikami, K. Tetrahedron Lett. 1998, 39, 1199.
28. (c) Sewald, N.; Seymour, L. C.; Burger, K.; Osipov, S. N.; Kolomiets, A. F.; Fokin, A. V. Tetrahedron: Asymmetry 1994, 5, 1051.
29. (d) Zanda, M.; Bravo, P.; Volonterio, A. In Asymmetric Fluoro-Organic Chemistry: Synthesis, Applications, and Future Directions; Ramachandran, P. V., Ed.; American Chemical Society Symposium Series; American Chemical Society: Washington, DC, 1999; in press.
30. Evans, D. A.; Bartroli, J.; Shih, T. L. J. Am. Chem. Soc. 1981, 103, 2127.
31. (a) Evans, D. A.; Gage, J. R.; Leighton, J. L.; Kim, A. S. J. Org. Chem. 1992, 57, 1961 and references therein.
32. For leading references on aldol reactions involving a-alkoxy-acetyloxazolidinones, see: (b) Evans, D. A.; Bender, S. L.; Morris, J. J. Am. Chem. Soc. 1988, 110, 2506.
33. (c) Keck, G. E.; Palani, A.; McHardy, S. F. J. Org. Chem. 1994, 59, 3113.
34. (d) Batchelor, M. J.; Gillespie, R. J.; Golec, J. M. C.; Hedgecock, C. J. R.; Jones, S. D.; Murdoch, R. Tetrahedron 1994, 50, 809.
35. (e) Fuhry, M. A. M.; Holmes, A. B.; Marshall, D. R. J. Chem. Soc., Perkin Trans. 1 1993, 2743.
36. (f) Jones, T. K.; Reamer, R. A.; Desmond, R.; Mills, S. G. J. Am. Chem. Soc. 1990, 112, 2998.
37. (g) Evans, D. A.; Kaldor, S. V.; Jones, T. K.; Clardy, J.; Stout, T. J. J. Am. Chem. Soc. 1990, 112, 7001.
38. (h) Piscopio, A. D.; Minowa, N.; Chakraborty, T. K.; Koide, K.; Bertinato, P.; Nicolaou, K. C. J. Chem. Soc., Chem. Commun. 1993, 617.
39. (i) Ku, T. W.; Kondrad, K. H.; Gleason, J. G. J. Org. Chem. 1989, 54, 3487.
40. (j) Mukaiyama, T.; Iwasawa, N. Chem. Lett. 1984, 753.
41. (k) Miyata, O.; Shinada, T.; Ninomiya, I.; Naito, T. Tetrahedron 1997, 53, 2421.
42. (l) Andrus, M. B.; Schreiber, S. L. J. Am. Chem. Soc. 1993, 115, 10420.
43. (m) Evans, D. A.; Gage, J. R.; Leighton, J. L. J. Am. Chem. Soc. 1992, 114, 9434.
44. (n) Evans, D. A.; Barrow, J. C.; Leighton, J. L.; Robichaud, A. J.; Sefkow, M. J. Am. Chem. Soc. 1994, 116, 12111.
45. (o) Loubinoux, B.; Sinnes, J.-L.; O'Sullivan, A. C.; Winkler, T. Helv. Chim. Acta 1995, 78, 122.
46. (p) Martin, S. F.; Dodge, J. A.; Burgess, L. E.; Limberakis, C.; Hartmann, M. Tetrahedron 1996, 52, 3229.
47. (q) Hulin, B.; Newton, L. S.; Lewis, D. M.; Genereux, P. E.; Gibbs, E. M.; Clark, D. A. J. Med. Chem. 1996, 39, 3897.
48. (r) Roush, W. R.; Marron, T. G.; Pfeifer, L. A. J. Org. Chem. 1997, 62, 474.
49. (s) Crimmins, M. T.; Choy, A. L. J. Org. Chem. 1997, 62, 7548.
50. (a) Bravo, P.; Capelli, S.; Meille, S. V.; Viani, F.; Zanda, M.; Kukhar, V. P.; Soloshonok, V. A. Tetrahedron: Asymmetry 1994, 5, 2009.
51. Gage, J. R.; Evans, D. A. Org. Synth. 1989, 68, 77-91.
52. Kricheldorf, H. R. Synthesis 1972, 695.
53. The low yields were due to partial decomposition of lithium enolate of 1, probably via fragmentation into a-benzyloxyketene and the corresponding deacylated N-lithium 2-oxazolidinone.
54. 19F NMR and HPLC.
55. See, for example: (a) Walker, M. A.; Heathcock, C. H. J. Org. Chem. 1991, 56, 5747. (b) Crimmins, M. T.; King, B. W.; Tabet, E. A. J. Am. Chem. Soc. 1997, 119, 7883.
56. See, for example: (a) Walker, M. A.; Heathcock, C. H. J. Org. Chem. 1991, 56, 5747. (b) Crimmins, M. T.; King, B. W.; Tabet, E. A. J. Am. Chem. Soc. 1997, 119, 7883.
57. 4 precomplexation of 2 were not investigated.
58. Osipov, S. N.; Kolomiets, A. F.; Fokin, A. V. Russ. Chem. Rev. 1992, 61, 798.
59. Gaussian 94, Revision C.3: Frisch, M. J.; Schlegel, G. W.; Trucks, H. B.; Gill, P. M. W.; Johnson, B. G.; Robb, M. A.; Cheeseman, J. R.; Keith, T.; Petersson, G. A.; Montgomery, J. A.; Raghavachari, K.; Al-Laham, M. A.; Zakrzewski, V. G.; Ortiz, J. V.; Foresman, J. B.; Cioslowski, J.; Stefanov, B. B.; Nanayakkara, A.; Challacombe, N.; Peng, C. Y.; Ayala, P. Y.; Chen, W.; Wong, M. W.; Andrés, J. L., Replogle, E. S.; Gomperts, R.; Martín, R. L.; Fox, D. J.; Binkley, J. S.; Defrees, D. J.; Baker, J.; Stewart, J. J. P.; Head-Gordon, M.; González, C.; Pople, J. A. Gaussian Inc., Pittsburgh, PA, 1995.
60. The preferential anti geometry of the N-substituent with respect to the fluorinated rest in 2 has been already observed in related structures. See, for example: Fustero, S.; Navarro, A.; Pina, B.; Asensio, A.; Bravo, P.; Crucianelli, M.; Volonterio, A.; Zanda, M. J. Org. Chem. 1998, 63, 6210.
61. 3, COOEt, and COOBn, attached to the C=N bond render the nitrogen lone pair unavailable to coordination by Lewis acids and the imine carbon strongly electrophilic: see ref 18.
62. (a) Iseki, K.; Oishi, S.; Taguchi, T.; Kobayashi, Y. Tetrahedron Lett. 1993, 34, 8147.
63. (b) Makino, Y.; Iseki, K.; Fujii, K.; Oishi, S.; Hirano, T.; Kobayashi, Y. Tetrahedron Lett. 1995, 36, 8147. Those reactions were proposed to take place via open TS involving chelated acyloxazolidinone enolates. It is worth noting that almost identical non-Evans-anti stereocontrol was described for the reactions of lithium, boron, and titanium enolates of chiral acyloxazolidinones with several fluorine-free pyruvic esters:
64. (c) Jacobson, I. C.; Reddy, G. P. Tetrahedron Lett. 1996, 37, 8263. For the sake of comparison, ethyl trifluoropyruvate E was also reacted with the chlorotitanium enolate of 1, using the identical optimized conditions found for the parent imine 2a. equation presented As expected, the reaction afforded a mixture of two diastereomeric adducts F (whose stereochemistry has not been determined yet) with low stereocontrol (66:34 ratio, 85%).
65. For very recent impressive progress in the field of enantiocontrolled aldol reactions of pyruvates see: (d) Evans, D. A.; Burgey, C. S.; Kozlowski, M. C.; Tregay, S. V. J. Am. Chem. Soc. 1999, 121, 686.
66. Evans, D. A.; Britton, T. C.; Ellman, J. A. Tetrahedron Lett. 1987, 28, 6141.
67. 4 in THF/water for achieving the same transformation appeared: Prashad, M.; Har, D.; Kim, H.-Y.; Repic, O. Tetrahedron Lett. 1998, 39, 7067.
68. X-ray data will be published separately.