Gold-Catalyzed Arylative and Alkenylative Semipinacol Rearrangements: Reaction Development, Mechanistic Insights, and Enantioselective Variant

Herein, we report the ligand-enabled gold-catalyzed arylative and alkenylative semipinacol rearrangements of allylic alkanols employing aryl and vinyl iodides as coupling partners. Building on our recent success in achieving enantioselective Au(I)/Au(III) redox catalysis using chiral P,N-ligands (ChetPhos), we now report the asymmetric arylative semipinacol rearrangement of allylic alkanols. Due to the strong carbophilic activation ability of gold, the reaction proceeds efficiently with allylic alkanols containing unactivated alkenes, in contrast to previous reports that required activated alkenes. Topographic steric maps, quantified via percentage buried volume (%VBur) analyses of the catalyst, key intermediates, and transition states, elucidate the steric factors governing the enantioinduction. The steric expansion in the South-Eastern (SE) quadrant (%VBur = 98.8%) originates from the twisting of the binaphthyl framework, generating a groove in the North-Eastern (NE) quadrant, facilitating Re-face alkene coordination.