Synthesis of α,β-Unsaturated Ketones from Aldehydes and Ketones Using 1,1-Di(boryl)alk-1-enes

An efficient method for the synthesis of α,β-unsaturated ketones through the boron-Wittig reaction of aldehydes and ketones using 1,1-di(boryl)alk-1-enes is reported. 1,1-Di(boryl)alk-1-enes are deprotonated at the γ-position to generate α,α-di(boryl)allyl anions, which react with aldehydes and ketones at the α-position to give boryl-1,3-dienes. Subsequent oxidation of the resulting boryl-1,3-dienes produces α,β-unsaturated ketones. Furthermore, α,β,γ,δ-unsaturated ketones were also synthesized using 1,1-di(boryl)alka-1,3-dienes.