Photoinduced Deoxygenative Boration of Unactivated Alcohols Involving In-Situ-Formed Alkyl Iodides

A method for the direct two-step/one-pot conversion of unactivated 1°, 2°, and 3° alcohols into the corresponding alkylboronate esters is reported. The hydroxy group is activated in situ by reaction with the Hendrickson "POP" reagent. The rapidly formed alkoxyphosphonium salt is then reacted with bis(catecholato)diboron under visible-light irradiation in the presence of stoichiometric amounts of lithium iodide. This one-pot protocol streamlines the two-step procedure, and it is operationally simple and scalable. The functional-group tolerance is broad.