Boron-promoted Deprotonative Conjugate Addition: Development of Geminal diborons as Versatile Soft Pronucleophiles and Acyl An-ion Equivalents

Abstract

Conjugate addition of α-boron stabilized carbanions is an underexplored reaction modality. Existing methods require deborylation of geminal di/triboryl alkanes and/or the presence of additional activating groups. We report the 1,4-addition of α,α-diboryl carbanions generated via deprotonation of corresponding geminal diborons. The methodology enabled a general route to highly substituted and synthetically useful γ,γ-diboryl ketones. The development of geminal diborons as soft pronucleophiles also enabled their use as acyl anion equivalents via one-pot tandem conjugate addition-oxidation sequence.

Boron-Promoted Deprotonative Conjugate Addition: Geminal Diborons as Soft Pronucleophiles and Acyl Anion Equivalents

“…In conclusion, the diboron retentive conjugate addition of geminal diboryl alkanes with enones and nitro-olefin has been developed for the first time . The methodology is applicable to both terminal and internal enones as conjugate acceptors, while α-substituents on these substrates are also tolerated.…”