Synthesis of a new bulky phosphite ligand and its application in the enantioselective hydrogenation

A new bulky phosphite ligand was synthesized and tested in the asymmetric Rh-catalyzed hydrogenation of a series of substrates, including dimethyl itaconate (up to 95% ee), alpha- and beta-dehydroamino acid derivatives (up to 88% and 76% ee, respectively). In the Ir-catalyzed hydrogenation of 2-methylindole, the use of iodine as an additive led to a significant increase in the enantioselectivity and conversion. The best result (64% ee) was obtained with [Ir(COD)Cl](2) as precatalyst. (C) 2018 Elsevier B.V. All rights reserved.