Iridium-Catalyzed -Selective Asymmetric Allylic Substitution Reaction via / Kinetic Resolution.

Chiral -olefin molecules are much more challenging targets in organic synthesis due to their thermodynamically unfavorable nature compared with that of their corresponding -olefin counterparts. Particularly, the transformations toward advanced chiral -olefin products from readily available -olefin precursors are faced with huge difficulties associated with the energetic uphill process. A possible solution to this issue is taking advantage of the different kinetic behaviors between - and -olefins. However, recognizing the different reactivities between - and -olefins poses great challenges for molecular catalysis. Herein, we report an Ir-catalyzed -selective asymmetric allylic substitution using oxindoles as nucleophiles via the kinetic resolution of / olefin mixtures. The higher reactivity of -allylic carbonates than their -counterparts in this reaction manifold originates from the faster oxidative addition of -allylic carbonates to the Ir(I) catalyst and the faster nucleophilic attack to -π-allyl-Ir intermediates than that to -π-allyl-Ir intermediates by external nucleophiles. When coupled with photoinduced olefin / isomerization, the same products are accessed from -allylic carbonates in up to 97% yield with 96% ee and >19:1 / ratio. The results reported in this study represent an unprecedented pattern in asymmetric Tsuji-Trost-type reactions, a class of fundamental transformations in organic synthesis, and provide a unique approach to advanced chiral -olefins.