Preparation of dihydroborole derivatives by a simple 1,1-carboboration route

Article abstract of DOI:10.1021/om300065m

2,3-Dihydroboroles are readily formed by treatment of dicyclopropylacetylene with the strongly electrophilic borane B(C ₆F₅)₃. The reaction involves a sequence of 1,1-carboboration reactions and proceeds via dienylborane intermediates. Consistent with this, the reaction of the conjugated enyne 15c with B(C ₆F₅)₃ leads to the formation of a dihydroborole.