Unveiling Hetero-Enyne Reactivity of Aryliminoboranes:Dearomative Hetero-Diels-Alder-Like Reactions

摘要

Being isoelectronic with alkynes,iminobor-anes with a polar B≡N triple bond have been exclusively investigated as a potent 1,2-dipole in synthetic chemistry.Herein,we disclose the unprecedented reactivity of aryliminoboranes via the BNCC n conjugation,namely hetero-enyne behavior.This allows for facile dearomative Diels-Alder-like reactions of aryliminoboranes with aldehydes.This cycloaddition features mild conditions,is catalyst-free,and has a broad substrate scope and good functional group tolerance.Kinetic and computational studies reveal its second-order reaction and concerted cyclization mechanism.This report unveils new synthetic application of iminoboranes beyond their classical reaction patterns.