A highly stereospecific synthesis of (E)- or (Z)-α-fluoro-α,β-unsaturated ketones 4, via a kinetically controlled Negishi palladium-catalyzed couplingreaction, was developed, providing an easy and general access to valuable fluorinated intermediates (pharmaceutical, peptide mimic, and so on). The synthesis involved a reaction between E/Z gem-bromofluoroolefins 2 and alkoxyvinylzinc species 6 under
From alpha-fluoroenones 2, a synthesis of (E) ketone oxime O-alkyl ethers 5 is reported with good to excellent yields. Then the first enantioselective reduction of these ketimines, via oxazaborolidine, is described with moderate to good enantiomeric excesses, leading to valuable chiral fluoroallylic amines 1. (c) 2006 Elsevier B.V. All rights reserved.
Diastereomeric Fluoroolefins as Peptide Bond Mimics Prepared by Asymmetric Reductive Amination of α-Fluoroenones
Asymmetric Synthesis of Alkyl Fluorides: Hydrogenation of Fluorinated Olefins
作者:Sudipta Ponra、Jianping Yang、Sutthichat Kerdphon、Pher G. Andersson
DOI:10.1002/anie.201903954
日期:2019.7
chiral fluorine‐containing molecules is important for several scientific disciplines. We herein disclose a straightforward method for the preparation of chiral organofluorine molecules that is based on the iridium‐catalyzed asymmetric hydrogenation of trisubstituted alkenyl fluorides. This catalytic asymmetric process enables the synthesis of chiral fluorine molecules with or without carbonyl substitution