Malkov, A. V., Vrankova, K., Stoncius, S. and Kocovsky, P. (2009) Asymmetric reduction of imines with trichlorosilane, catalyzed by sigamide, an amino acid-derived formamide: scope and limitations. Journal of Organic Chemistry, 74(16), pp. 5839-5849. (doi: 10.1021/jo900561h)
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Publisher's URL: http://dx.doi.org/10.1021/jo900561h
Abstract
Enantioselective reduction of ketimines 6-10 With trichlorosilane can be catalyzed by the N-methyl valine-derived Lewis-basic formamide (S)-23 (Sigamide) with high enantioselectivity (<= 97% ee) land low catalyst loading, (1 - 5 mol %) at room temperature in toluene. The reaction is efficient with ketimines derived from aromatic amines (aniline and anisidine) and aromatic, heteroaromatic, conjugated, and even nonaromatic ketones 1-5, in which the steric difference between the alkyl groups R-1 and R-2 is sufficient. Simple nitrogen heteroaromatics (8a,b,d) exhibit low enantioselectivities due to the competing coordination of the reagent but increased steric hindrance in the Vicinity of the nitrogen (8c,e) results in a considerable improvement. Cyclic imines 32d-d exhibited low to modest enantioselectivities.
Item Type: | Articles |
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Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Malkov, Dr Andrei and Stoncius, Mr Sigitas and Vrankova, Miss Kvetoslava and Kocovsky, Professor Pavel |
Authors: | Malkov, A. V., Vrankova, K., Stoncius, S., and Kocovsky, P. |
College/School: | College of Science and Engineering > School of Chemistry |
Journal Name: | Journal of Organic Chemistry |
Publisher: | American Chemical Society |
ISSN: | 0022-3263 |
ISSN (Online): | 1520-6904 |
Published Online: | 16 June 2009 |
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