Iron-Catalyzed Divergent Borylation of α-Aryl-Substituted Allylic Alcohols.

Herein, an iron-catalyzed divergent borylation of α-aryl-substituted allylic alcohols is reported. Precise tuning of the reaction system enables control over the chemo-, regio-, and stereoselectivities, providing divergent access to three valuable classes of organoboron compounds: β-borylated alkylarenes, γ-borylated alkylarenes, and allylic boronates. Mechanistic studies reveal that β-borylated alkylarenes are formed via a sequential hydrodeoxygenation-olefin isomerization-hydroboration cascade, γ-borylated alkylarenes are produced through hydrodeoxygenation followed by selective hydroboration of β,γ-olefin intermediates, and allylic boronates are generated via a mechanism featuring a six-membered cyclic transition state.