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An investigation of the observed, but counter-intuitive, stereoselectivity noted during chiral amine synthesis via N-chiral-ketimines.

ABSTRACT: The default explanation for good to high diastereomeric excess when reducing N-chiral imines possessing only mediocre cis/trans-imine ratios (>15% cis-imine) has invariably been in situ cis-to-trans isomerization before reduction; but until now no study unequivocally supported this conclusion. The present study co-examines an alternative hypothesis, namely that some classes of cis-imines may hold conformations that erode the inherent facial bias of the chiral auxiliary, providing more of the trans-imine reduction product than would otherwise be expected. The ensuing experimental and computational (DFT) results favor the former, pre-existing, explanation.

SUBMITTER: Nugent TC

PROVIDER: S-EPMC3817511 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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An investigation of the observed, but counter-intuitive, stereoselectivity noted during chiral amine synthesis via N-chiral-ketimines.

Nugent Thomas C TC Williams Richard Vaughan RV Dragan Andrei A Méndez Alejandro Alvarado AA Iosub Andrei V AV

Beilstein journal of organic chemistry 20131015

The default explanation for good to high diastereomeric excess when reducing N-chiral imines possessing only mediocre cis/trans-imine ratios (>15% cis-imine) has invariably been in situ cis-to-trans isomerization before reduction; but until now no study unequivocally supported this conclusion. The present study co-examines an alternative hypothesis, namely that some classes of cis-imines may hold conformations that erode the inherent facial bias of the chiral auxiliary, providing more of the tra ...[more]

PMID: 24204422

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