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

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.