E-Stereospecific 1,1-Carboboration of Terminal Arylalkynes with [IB(C₆F₅)₃]^–

Abstract

The difunctionalization of alkenes and alkynes is a simple and powerful strategy for the synthesis of various organic compounds and has been used to synthesize various important natural products, drug molecules and fine chemical products. The different effects of halo anions, substrates, solvents, temperature and reaction time to the stereospecific and reactivities of 1,1-carboborations of alkynes and B(C6F5)s were studied, meanwhile the corresponding catalytic mechanisum has been expoled. A convenient large-scale preparation method for the stereoselective (E)-1,1-carboboration products has been developed. The catalytic reactivities of ring-opening polymerization of cyclohexene oxide (CHO) have also been explored with different stereo-carboboranes isolated from 1,1-carboboration reaction, and it is noted that the stereospecificity E-or Z-has shown ambiguously different activities. To develop a stereo-specific approach in the synthesis of vinylboranes will not only be very important for the difunctionalization of alkenes and alkynes, but also for the novel stereospecificity organoborons.