Stereoselective titanium-mediated syn-aldol reaction from a lactate-derived chiral ethyl ketone

Tetrahedron Letters

Volumn 45, Issue 28, 2004, Pages 5379-5382

  Solsona, Joan G ^a   Romea, Pedro ^a   Urpí, Fèlix ^a  

^a UNIVERSITY OF BARCELONA   (Spain)

Author keywords

Aldol reactions; Asymmetric reactions; Lewis acids; Titanium enolates

Indexed keywords

2 BENZYLOXY 3 PENTANONE; ALDEHYDE; ALKANONE; KETONE DERIVATIVE; LACTIC ACID; LEWIS ACID; TITANIUM DERIVATIVE; UNCLASSIFIED DRUG;

ALDOL REACTION; ARTICLE; CHIRALITY; DIASTEREOISOMER; STEREOCHEMISTRY;

EID: 2942643907     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2004.05.077     Document Type: Article

References (29)

1. Mukaiyama T. Org. React. 28:1982;203-331
2. Mahrwald R. Chem. Rev. 99:1999;1095-1120
3. Walker M.A., Heathcock C.H. J. Org. Chem. 56:1991;5747-5750
4. Yan T.-H., Lee H.-C., Tan C.-W. Tetrahedron Lett. 34:1993;3559-3562
5. Wang Y.-C., Hung A.-W., Chang C.-S., Yan T.-H. J. Org. Chem. 61:1996;2038-2043
6. Ghosh A.K., Onishi M. J. Am. Chem. Soc. 118:1996;2527-2528
7. Crimmins M.T., King B.W., Tabet E.A. J. Am. Chem. Soc. 119:1997;7883-7884
8. Crimmins M.T., King B.W., Tabet E.A., Chaudhary K. J. Org. Chem. 66:2001;894-902
9. Ghosh A.K., Kim J.-H. Tetrahedron Lett. 43:2002;5621-5624
10. Crimmins M.T., McDougall P.J. Org. Lett. 5:2003;591-594
11. Ferreró M., Galobardes M., Martín R., Montes T., Romea P., Rovira R., Urpí F., Vilarrasa J. Synthesis. 2000;1608-1614
12. Solsona J.G., Romea P., Urpí F., Vilarrasa J. Org. Lett. 5:2003;519-522
13. The synthetic utility of lactate-derived ketones in stereoselective syn and anti boron-mediated aldol reactions was firmly established by Paterson. See: Paterson I., Wallace D.J., Velázquez S.M. Tetrahedron Lett. 35:1994;9083-9086
14. Paterson I., Wallace D.J. Tetrahedron Lett. 35:1994;9087-9090
15. Paterson I., Wallace D.J., Cowden C.J. Synthesis. 1998;639-652
16. For previous boron- and titanium-mediated aldol reactions based on α-silyloxy ketones derived from lactic acid, see: Figueras S., Martín R., Romea P., Urpí F., Vilarrasa J. Tetrahedron Lett. 38:1997;1637-1640
17. Galobardes M., Gascón M., Mena M., Romea P., Urpí F., Vilarrasa J. Org. Lett. 2:2000;2599-2602
18. For a catalytic aldol process based on the trichlorosilyl enolates from a lactate-derived ketone, see Denmark S.E., Pham S.M. Org. Lett. 3:2001;2201-2204
19. 13C NMR spectra as well as specific rotations with those previously reported by us. See Ref. 5. The absolute configuration of anti-aldols 4 has not been established
20. Method B afforded a 15:85 mixture of 2d:3d in the case of benzaldehyde
21. 4) and concentrated. The resulting oil was analyzed by HPLC and purified by flash chromatography on silica gel (hexanes/EtOAc)
22. (a) The stereochemical outcome of the aldol reaction of boron enolates derived from oxazolidinones in the presence of Lewis acids has been rationalized using this model. See Ref. [3a]
23. 4 equivalents can produce the abstraction of a chloride anion or the formation of chloro bridged species. See Ref. [3e]
24. Masamune S., Choy W., Petersen J.S., Sita L.R. Angew. Chem., Int. Ed. Engl. 24:1985;1-30
25. Roush W.R., Palkowitz A.D., Ando K. J. Am. Chem. Soc. 112:1990;6348-6359
26. Selected physical and spectroscopic data.
27. 6 (dr 65:35). In the case of adduct 7, a single hemiacetal 9 was observed. Selected NMR data:
28. Esteve C., Ferreró M., Romea P., Urpí F., Vilarrasa J. Tetrahedron Lett. 40:1999;5083-5086
29. Solsona J.G., Romea P., Urpí F. Org. Lett. 5:2003;4681-4684