Rationalising the effect of reducing agent on the oxazaborolidine-mediated asymmetric reduction of N-substituted imines

Tetrahedron Letters

Volumn 45, Issue 4, 2004, Pages 853-855

  Kirton, Eirene H M ^a,b   Tughan, Gary ^c,d   Morris, Russell E ^a   Field, Robert A ^a,b  

^a UNIVERSITY OF ST ANDREWS   (United Kingdom)

^b UNIVERSITY OF EAST ANGLIA   (United Kingdom)

^c GLAXOSMITHKLINE   (United Kingdom)

^d ASTRAZENECA   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

IMINE; OXAZABOROLIDINE DERIVATIVE; REDUCING AGENT;

ARTICLE; ASYMMETRIC CATALYSIS; REDUCTION; STEREOCHEMISTRY; SUBSTITUTION REACTION;

EID: 0346787842     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2003.11.021     Document Type: Article

References (18)

1. Corey E.J., Bakshi R.K., Shibata S. J. Am. Chem. Soc. 109:1987;5551-5553. Reviewed in: Srebnik M., Deloux L. Chem. Rev. 93:1993;763-784 Corey E.J., Helal C.J. Angew. Chem., Int. Ed. 37:1998;1986-2012.
2. Corey E.J., Bakshi R.K., Shibata S. J. Am. Chem. Soc. 109:1987;5551-5553. Reviewed in: Srebnik M., Deloux L. Chem. Rev. 93:1993;763-784 Corey E.J., Helal C.J. Angew. Chem., Int. Ed. 37:1998;1986-2012.
3. Corey E.J., Bakshi R.K., Shibata S. J. Am. Chem. Soc. 109:1987;5551-5553. Reviewed in: Srebnik M., Deloux L. Chem. Rev. 93:1993;763-784 Corey E.J., Helal C.J. Angew. Chem., Int. Ed. 37:1998;1986-2012.
4. For selected recent examples of ketone reductions with immobilised oxazaborolidines see: Price M.D., Sui J.K., Kurth M.J., Schore N.E. J. Org. Chem. 67:2002;8086-8089 Schunicht C., Biffis A., Wulff G. Tetrahedron. 56:2000;1693-1699. and references cited therein.
5. For selected recent examples of ketone reductions with immobilised oxazaborolidines see: Price M.D., Sui J.K., Kurth M.J., Schore N.E. J. Org. Chem. 67:2002;8086-8089 Schunicht C., Biffis A., Wulff G. Tetrahedron. 56:2000;1693-1699. and references cited therein.
6. (a) Cho B.T., Ryu M.H., Chun Y.S., Dauelsburg C., Wallbaum S., Martens J. Bull. Korean Chem. Soc. 15:1994;53-57 Cho B.T., Chun Y.S. J. Chem. Soc., Perkin Trans. 1. 1990;3200-3201.
7. (a) Cho B.T., Ryu M.H., Chun Y.S., Dauelsburg C., Wallbaum S., Martens J. Bull. Korean Chem. Soc. 15:1994;53-57 Cho B.T., Chun Y.S. J. Chem. Soc., Perkin Trans. 1. 1990;3200-3201.
8. Cho B.T., Chun Y.S. Tetrahedron: Asymmetry. 3:1992;337-340.
9. Sakai T., Yan F., Uneyama K. Synlett. 1995;753-754 Sakai T., Yan F., Kashino S., Uneyama K. Tetrahedron. 52:1996;233-244.
10. Sakai T., Yan F., Uneyama K. Synlett. 1995;753-754 Sakai T., Yan F., Kashino S., Uneyama K. Tetrahedron. 52:1996;233-244.
11. The low yield of amino-ester 3 is accompanied by formation of the corresponding amino-alcohol (49% yield), albeit of the R-configuration (45% ee) (the change in stereochemistry is not accounted for). On moving from borane-THF to the less reactive catecholborane, formation of the amino-alcohol was no longer evident.
12. 3b In THF (1.5 mL), phenyl(1-phenylethylidene)amine 6 (25 mg, 130 μmol), (S)-methyl-CBS-oxazaborolidine 1 , (13 μmol, 10 mol %) were stirred under nitrogen for 10 min. Reducing agent (150 μmol) was added and the reaction was stirred at room temperature. Reactions were assessed by HPLC after 1 h (250 × 4.6 mm Chiralcel OD-H column; 5% ethanol in heptane; 0.5 mL/min; detection at 215/254 nm).
13. Morimoto T., Nakajima N., Achiwa K. Tetrahedron: Asymmetry. 6:1995;23-26.
14. Corey E.J., Azimioara M., Sarshar S. Tetrahedron Lett. 33:1992;3429-3430.
15. Corey E.J., Link J.O., Bakshi R.K. Tetrahedron Lett. 33:1992;7107-7110 Jones D.K., Liotta D.C., Shinkai I., Mathre D.J. J. Org. Chem. 58:1993;799-801.
16. Corey E.J., Link J.O., Bakshi R.K. Tetrahedron Lett. 33:1992;7107-7110 Jones D.K., Liotta D.C., Shinkai I., Mathre D.J. J. Org. Chem. 58:1993;799-801.
17. These models are based on the premise that only the trans form of the imine is subject to oxazaborolidine-catalysed reduction.
18. The effect of imine structure, including N-substitution, on the stereoselectivity of oxazaborolidine-catalysed imine reduction has been noted (see Ref. 3).