Double hydroboration of dienes is the addition of a hydrogen and a boryl group to the twodouble bonds of a diene molecule and represents a straightforward and effective protocol toprepare synthetically versatile bis(boryl)alkanes, provided that this reaction occurs selectively.However, this reaction can potentially yield several isomeric organoboron products, and it stillremains a challenge to control the regioselectivity of this reaction, which allows the selectiveproduction of a single organoboron product, in particular, for a broad scope of dienes. Byemploying a readily available cobalt catalyst, here we show that this double hydroborationyields synthetically useful gem-bis(boryl)alkanes with excellent regioselectivity. In addition, thescope of dienes for this reaction is broad and encompasses a wide range of conjugated andnon-conjugated dienes. Furthermore, mechanistic studies indicate that this cobalt-catalyzeddouble hydroboration occurs through boryl-directed chain-walking hydroboration of alkenylboronatesgenerated from anti-Markovnikov 1,2-hydroboration of 1,n-diene.
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