Access to Enantioenriched Allylic Alcohols via Peptide‐Mimic Phosphonium Salt‐Catalyzed Asymmetric Aerobic Hydroxylation

Comprehensive Summary The development of catalytic asymmetric methods that enable access to value‐added functionalities or structures, exemplified by allylic alcohols, is a highly interesting yet challenging topic from both academic and industrial perspectives. However, before recent advances in chemical catalysis, there were scarce protocols toward constructing enantioenriched tertiary allylic alcohol scaffolds. In this context, peptide‐mimic phosphonium salts were found to be highly efficient in catalytic asymmetric α‐hydroxylation of α,β‐unsaturated and/or β,ϒ‐unsaturated compounds with satisfactory regio‐ and stereochemical outcomes (up to 97% yield and 95% ee). This methodology tolerates a broad array of substrates and thus provides an expeditious and unified platform for the assembly of enantioenriched tertiary allylic alcohols by avoiding the use of additional reductants and expensive metal catalysts. Furthermore, the power of this protocol is enlarged by simple conditions and the use of air as a source of hydroxyl functionality.