Asymmetric Alkenylation of Enones and Other α,β-Unsaturated Carbonyl Derivatives Using Chiral 3,3′-Disubstituted Binaphthols and Boronates
Loading...
Date
2009-05-22T18:14:25Z
Authors
Guobadia, Bobby
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Various α,β-unsaturated carbonyl compounds and derivatives were explored in order to expand the range of substrates for the 1,4-addition of alkenylboronates using 3,3′-disubstituted binaphthols. Enones 2.60 were examined and found to be suitable for conjugate addition under our proposed reaction conditions.
The asymmetric 1,4-additions of alkenylboronates to enones 2.60 using catalytic amounts of 3,3′-disubstituted binaphthols was shown to occur with moderate to good yields and high enantioselectivities. The chiral products could serve as enantioenriched substrates for further transformation such as asymmetric reduction, which was performed with good yield and selectivity. The absolute configuration for the alkenylation of enones was also confirmed to be the (R) enantiomer using (S)-3,3′-disubstituted binaphthols via X-ray crystallographic analysis.
Investigations into selective Baeyer-Villiger oxidation of 1,4-addition products of enones was also examined. Although the desire ester products were not obtained, intriguing informative findings were still obtained from the investigation.
Description
Keywords
asymmetric conjugate addition, enones, alkenylboronates, α,β-unsaturated carbonyl compounds