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Asymmetric Tandem Conjugate Addition–Aldol Condensation with N‐Acryloyloxazolidines Derived from 2‐Phenylglycinol

Asymmetric Tandem Conjugate Addition–Aldol Condensation with N‐Acryloyloxazolidines Derived from... The tandem 1,4‐addition–aldol condensation reaction of diethylzinc, α,β‐unsaturated chiral enantiopure oxazolidines derived from 2‐phenylglycinol, and carbonyl compounds is disclosed. The reaction proceeds through a radical‐polar crossover mechanism involving the aldol condensation of a trisubstituted zinc enolate through a Zimmerman–Traxler transition state. Installation of a 2‐pyridine moiety at the hemiaminal position of the chiral auxiliary allows obtaining both excellent asymmetric induction and diastereoselectivity (up to >90 % de). The developed protocol is suitable for aromatic and aliphatic aldehydes, as well as ketones. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Asian Journal of Organic Chemistry Wiley

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References (19)

Publisher
Wiley
Copyright
© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim
ISSN
2193-5807
eISSN
2193-5815
DOI
10.1002/ajoc.201600501
Publisher site
See Article on Publisher Site

Abstract

The tandem 1,4‐addition–aldol condensation reaction of diethylzinc, α,β‐unsaturated chiral enantiopure oxazolidines derived from 2‐phenylglycinol, and carbonyl compounds is disclosed. The reaction proceeds through a radical‐polar crossover mechanism involving the aldol condensation of a trisubstituted zinc enolate through a Zimmerman–Traxler transition state. Installation of a 2‐pyridine moiety at the hemiaminal position of the chiral auxiliary allows obtaining both excellent asymmetric induction and diastereoselectivity (up to >90 % de). The developed protocol is suitable for aromatic and aliphatic aldehydes, as well as ketones.

Journal

Asian Journal of Organic ChemistryWiley

Published: Jan 1, 2017

Keywords: ; ; ; ;

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