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
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.
Organic synthesis using haloboration reaction. Part 9. A direct and selective synthesis of (Z,Z)-1-bromo-1,3-dienes and (E,Z)-1,3-dienes by the hydroboration-bromoboration sequence of two alkynes
1-Alkenyldibromoboranes readily obtainable by the hydroboration of first alkynes with dibromoborane-dimethylsulfide followed by treatment with tribromoborane, react without any difficulty with second 1-alkynes as bromoborating agents to give (1-a1keny1)(2-bromo-1-alkeny)- bromoboranes (5). The reaction of 5 with iodine in the presence of potassium acetate provides (Z,Z)-1-bromo-1,3-dienes (6), specifically