ORGANIC SYNTHESIS USING HALOBORATION REACTION. A DIRECT AND SELECTIVE SYNTHESIS OF (<i>Z</i>,<i>Z</i>)-1-BROMO-1,3-DIENES BY USING HALOBORATION-HYDROBORATION OF TWO ALKYNES

Abstract

Abstract Bis(2-bromo-1-alkenyl)bromoboranes, readily obtainable by the bromoboration of 1-alkynes with tribromoborane, have been found to be converted in situ into the corresponding borohydrides by the reduction with diisobutylaluminum hydride. Such borohydrides are effective as hydroborating agents for internal alkynes to provide bis(bromoalkenyl)(alkenyl)boranes, which react with iodine in the presence of potassium acetate to give (Z, Z)-1-bromo-1,3-dienes, specifically.