Efficient 1,4-asymmetric induction utilizing electrostatic interaction between ligand and substrate in the asymmetric hydrogenation of didehydrodipeptides

Abstract

Electrostatic interaction between the amino group of the achiral 3-dimethylaminopropylidenebismethylenebis(diphenylphosphine)(1) and the carboxy group of the substrate enabled an effective 1,4-asymmetric induction in the Rh^I-catalysed hydrogenation of didehydrodipeptides, to give (S,S)- or (R,R)-products selectively. The selectivity reached up to 94% diastereoisomeric excess with acetyl didehydrodipeptides and 92% with benzyloxycarbonyl substrates.