An environmentally benign catalyst, the N,N′-dioxide-FeCl3 complex, has been developed for the asymmetric intramolecular Cannizzaro reaction. Aryl and alkyl glyoxal monohydrates were applied to obtain α-hydroxy acid esters with excellent results. Deuterium-label and control experiments shed light on the reaction mechanism.
Asymmetric addition of arylboronic acids to glyoxylate catalyzed by a ruthenium/Me-BIPAM complex
The enantioselective synthesis of α-hydroxy esters by ruthenium-catalyzed 1,2-addition of arylboronic acids to tert-butyl glyoxylate is described. The use of RuCl2(PPh3)3 with (R,R)-Me-BIPAM gave optically active mandelic acids of up to 99% ee. Addition of a fluoride salt such as potassium fluoride (KF) or caesium fluoride (CsF) was effective for achieving high enantioselectivities. The Royal Society of Chemistry 2012.