作者:Hélène Dentel、Isabelle Chataigner、Jean-François Lohier、Mihaela Gulea
DOI:10.1016/j.tet.2012.01.039
日期:2012.3
Asymmetric thia-Diels-Alder reactions involving new dithioesters bearing a chiral auxiliary are described, with diastereoselectivities up to 78%. Double-stereodifferentiating experiments employing chiral substrates in the presence of a chiral Lewis acid catalyst have been also carried out and, in this case, a diastereomeric excess of 90% was reached. The absolute stereochemistry of cycloadducts resulting from dithiooxalates and carbonyloxazolidinone dithioesters was assigned based on an X-ray structure and chemical correlation. In order to rationalize the sense of the chiral induction, stereochemical models for Cu(II)/bis(oxazoline)/dithioester complexes are proposed. (C) 2012 Elsevier Ltd. All rights reserved.