α,ω-Functionalized 2,4-Dimethylpentane Dyads and 2,4,6-Trimethylheptane Triads through Asymmetric Hydrogenation

摘要

Chiral analogues of the Crabtree catalysts,[1] [Ir(cod)(py)(PR3)PF6] (that is, [M(N,P)*] systems; cod=cycloocta-l,5-diene, py=pyridine) are excellent enantioselective catalysts for hydrogenation reactions of trisubstituted alkenes,[2] and have been used extensively to reduce alkenes that are largely unfunctionalized insofar as they do not contain strongly coordinating groups.[3], [4] Consequently, asymmetric hydrogenations are potentially possible for a broad range of substrates for which most other chiral catalysts are not effective.