Asymmetric Double-Bond Isomerization of Alkenes With Photoredox/Chromium Combined Catalysis.

The asymmetric contra-thermodynamic double-bond isomerization of alkenes remains a formidable challenge due to the lack of activating functional groups for chiral catalyst recognition. Here we report a photoredox/chromium combined catalysis that enables highly asymmetric double-bond isomerization of internal alkenes to enantioenriched terminal alkenes. This atom-economical transformation proceeds via SET/PT or HAT-mediated generation of a chiral allylchromium intermediate, followed by enantiodetermining protodemetalation. The protocol exhibits good functional group compatibility and has been successfully applied to the concise asymmetric total synthesis of (+)-licochalcone E.