Enantio- and chemoselective Bronsted-acid/ Mg(~nBu)_2 catalysed reduction of α-keto esters with catecholborane

摘要

The first enantio- and chemoselective Brensted-acid catalysed reduction of a-keto esters with catecholborane has been developed. The α-hydroxy esters were obtained under mild reaction conditions in virtually quantitative yields and excellent enantioselectivities. With slight modifications both enantiomers can be obtained without any loss of selectivity.