<i>C</i><sub>2</sub>-Symmetric Chiral Bisoxazolines as Hydrogen-Bond-Acceptor Catalysts in Enantioselective Aldol Reaction of β-Carbonyl Acids with Trifluoroacetaldehyde Hemiacetals
作者:Zhen-Yan Yang、Jun-Liang Zeng、Nan Ren、Wei Meng、Jing Nie、Jun-An Ma
DOI:10.1021/acs.orglett.6b03256
日期:2016.12.16
C2-symmetric chiral bisoxazoline is demonstrated to use hydrogen bonding to catalyze an important family of aldolreactions of trifluoroacetaldehyde hemiacetals with various β-carbonyl acids. This reaction is highly enantioselective, delivering chiral nonracemic trifluoromethylated alcohols with excellent optical purity and good isolated yields. This concept of relaying chiral information via a chiral hydrogen-bond
The magnesium complex (1) has been found to undergo fixation of carbondioxide and the resulting 1-carboxylato-complex (2) transfers the carboxylato group to active methylene compounds (3) including acetophenone, benzylideneacetone, β-ionone, and S-benzyl thioacetate, under mild conditions.