Double Asymmetric Hydrogenation of (E)‐2‐Substituted‐4‐oxo‐2‐alkenoic Acids: An Efficient Synthesis of Chiral α, γ‐Disubstituted γ‐Butyrolactones

Abstract Optical pure α , γ ‐disubstituted γ ‐butyrolactones moieties are versatile building blocks for the synthesis of many drugs and natural products. Herein we report a straightforward and efficient approach to afford a series of chiral α , γ ‐disubstituted γ ‐butyrolactones with excellent results (up to 98 % yield, up to >99 : 1 d.r ., and up to >99 % ee ) through the double asymmetric hydrogenation of the ( E )‐2‐methyl‐4‐oxo‐2‐alkenoic acids utilizing the rhodium/JosiPhos catalytic system.