Base-catalysed reductive relay hydroboration of allylic alcohols with pinacolborane to form alkylboronic esters

An unprecedented base-catalysed reductive relay hydroboration of allylic alcohols is described. Commercially available n BuLi was found to be a robust transition metal-free initiator for this protocol, affording various boronic esters in high yield and selectivity. Mechanistically, this methodology involves a one-pot three-step successive process (dehydrocoupling/allylic hydride substitution/anti-Markovnikov hydroboration). A novel reductive relay hydroboration of allylic alcohols with pinacolborane using n BuLi as an efficient initiator is reported.