Cyclopropanation / Carboboration Reactions of Enynes with B(C6F5)3
- Publisher: American Chemical Society
Stoichiometric reaction of B(C6F5)3 with 1,6-enynes are shown to proceed via initial cyclopropanation and formal 1,1-carboboration. Depending on the substitution on the alkene moiety, subsequent ring-opening of the cyclopropane affords either cyclopentane or cyclohexane derivatives in which the C6F5 and B(C6F5)2 adopt a 1,4-positioning. Mechanistically this transformation involves π-activation of the alkyne moiety which triggers cyclopropanation, followed by carboboration. Both the cyclopropanation and subsequent ring-opening are shown to be stereospecific. Both cyclopropanation and 1,4-carboborated products were employed as Lewis acid components in frustrated Lewis pair activation of H2 and CO2.