Magnesium Halide-Catalyzed Anti-Aldol Reactions of Chiral N-Acylthiazolidinethiones

Organic Letters

Volumn 4, Issue 7, 2002, Pages 1127-1130

  Evans, David A ^a   Downey, C Wade ^a   Shaw, Jared T ^a   Tedrow, Jason S ^a  

^a HARVARD UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

DYES, REAGENTS, INDICATORS, MARKERS AND BUFFERS; MAGNESIUM; THIAZOLE DERIVATIVE;

ARTICLE; CATALYSIS; CHEMICAL STRUCTURE; CHEMISTRY; CONFORMATION; SYNTHESIS;

CATALYSIS; INDICATORS AND REAGENTS; MAGNESIUM; MODELS, MOLECULAR; MOLECULAR CONFORMATION; THIAZOLES;

EID: 0037018454     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol025553o     Document Type: Article

References (20)

1. (a) Yoshikawa, N.; Kumagai, N.; Matsunaga, S.; Moll, G.; Ohshima, T.; Suzuki, T.; Shibasaki, M. J. Am. Chem. Soc. 2001, 723, 2466-2467 and references therein.
2. (b) Trost, B. M.; Ito, H.; Silcoff, E. R. J. Am. Chem. Soc. 2001, 123, 3367-3368 and references therein.
3. (c) Trost, B. M.; Silcoff, E. R.; Ito, H. Org. Lett. 2001, 3, 2497-2500.
4. For a related soft-enolization procedure, see: Tirpak, R. E.; Olsen, R. S.; Rathke, M. W. J. Org. Chem. 1985, 50, 4877-4879 and references therein.
5. Evans, D. A.; Tedrow, J. S., Shaw, J. T.; Downey, C. W. J. Am. Chem. Soc. 2002, 124, 392-393.
6. (a) Crimmins, M. T.; King, B. W.; Tabet, E. A.; Chaudhary, K. J. Org. Chem. 2001, 66, 894-902 and references therein.
7. (b) Fujita, E.; Nagao, Y. Adv. Heterocycl. Chem. 1989, 49, 1-36.
8. (c) Nagao, Y.; Yamada, S.; Kumagai, T.; Ochiai, M.; Fujita, E. J. Chem. Soc., Chem. Commun. 1985, 1418-1420.
9. (a) Evans, D. A.; Bartroli, J.; Shin, T. L.; J. Am. Chem. Soc. 1981, 103, 2127-2129.
10. (b) Evans, D. A., Rieger, D. L., Bilodeau, M. T., Urpi, F. J. Am. Chem. Soc. 1991, 113, 1047-1049.
11. (c) Evans, D. A., Nelson, J. V.; Taber, T. Top. Stereochem. 1982, 13, 1-115.
12. (d) Gage, J.; Evans, D. A. Org. Synth. 1990, 68, 83-91.
13. Delaunay, D.; Toupet, L.; Le Corre, M. J. Org. Chem. 1995, 60, 6604-6607.
14. Silylated adducts are configurationally stable under the reaction conditions.
15. Further experiments to eliminate epimerization as a source of isomerization have been conducted and will be reported in due course.
16. (a) Evans, D. A.; Ennis, M. D.; Mathre, D. J. J. Am. Chem. Soc. 1982, 104, 1737-1739.
17. (b) Evans, D. A.; Nelson, S. G. J. Am. Chem. Soc. 1997, 119, 6452-6453.
18. For the sake of space, we have not presented the analogous five-coordinate Mg transition states. We speculate that the O-Mg-O=C bond angle in these complexes will also be ∼90° with the O=C (RCHO) ligand oriented in the equatorial plane and the O-enolate ligand in axial position to optimize the electronic effects conferred on the reaction partners by the metal center.
19. Li, Y.; Paddon-Row: M. N.; Houk, K. N. J. Org. Chem. 1990, 55, 481-493.
20. Transition-structure optimizations were performed at the PM3 level using the Spartan Semiempirical Program 5.0 (Wavefunction Inc., Irvine, CA 92715) on a Silicon Graphics Impact 10000 (195 MHz, 128 M RAM) running IRIX 6.2. Calculations were performed without solvent using these parameters: optcycle = 2000, maxcycle = 2000, charge = 0, multiplicity = 0. Calculations converged (energy difference between cycles <0.0005 kcal/mol) in ≤ 4 h CPU time.