Cobalt‐Catalyzed Diborylation of 1,1‐disubstituted Vinylarenes: A Practical Route to Branchedgem‐Bis(boryl)alkanes

Abstract

We report the first catalytic diborylation of 1,1‐disubstituted vinylarenes with pinacolborane using a cobalt catalyst generated from bench‐stable Co(acac)2 and xantphos. A wide range of 1,1‐disubstituted vinylarenes underwent this transformation to produce the corresponding gem‐bis(boryl)alkanes in modest to high yields. This cobalt‐catalyzed reaction can be readily conducted on a gram scale without the use of a dry box and represents a practical and effective approach to prepare a wide range of branched gem‐bis(boryl)alkanes.

Progress in Cobalt Complexes for Enabling Asymmetric Hydrogenation, H2 Production Catalysis and Alkene/Alkyne Hydro‐functionalization: A Review

“…The success of this reaction was highlighted by its exceptional compatibility with various functional groups even under mild reaction conditions. [132] The progression of the hydroboration reaction involves an initial step of anti-Markovnikov hydroboration. This step leads to the formation of a trans-vinylboronate intermediate, which is subsequently followed by an additional hydroboration event to generate the desired 1,1-diboronate product.…”

“…Remarkably, this process exhibited remarkable tolerance towards a diverse range of functional groups. The success of this reaction was highlighted by its exceptional compatibility with various functional groups even under mild reaction conditions [132] . The progression of the hydroboration reaction involves an initial step of anti‐Markovnikov hydroboration.…”