Enantioselective Hydrogenation of Imines Using Cooperative Catalysis

Key words

iridium - Brønsted acid - cooperative catalysis

Significance

Optically active amines are common in many fine chemicals, agrochemicals, and pharmaceuticals. The authors report a cooperative metal-organo catalytic system utilizing a chiral Brønsted acid and an achiral iridium catalyst (see below for a Review on transfer hydrogenation).

Review

C. Zheng, S.-L. You Chem. Soc. Rev. 2012, 41, 2498–2518.

Comment

The authors have reported the cooperative use of a chiral iridium catalyst with a chiral phosphoric acid in the asymmetric hydrogenation of acyclic imines with H₂ (J. Am. Chem. Soc. 2008, 130, 14450). Here, they report an achiral iridium catalyst with a chiral phosphoric acid in a similar reaction. Alkyl imines, which are known to be difficult substrates for asymmetric hydrogenation, were shown to be excellent substrates in this system, giving enantioselectivities up to 97%.