Hetero Diels–Alder reactions of isolable N-borylenamines

Abstract

A new strategy for N-borylenamines by reaction of 2-alkynyl benzyl azides with B(C₆F₅)₃ was developed. This novel 1,3-carboboration reaction proceeded via a 5-exo-dig cyclization/formal 1,1-carboboration/B(C₆F₅)₂ shift reaction sequence. Additionally, N-borylenamines can undergo hetero Diels–Alder (HDA) reactions with a variety of dienophiles. Our results are an attractive complement to HDA reactions.