Carbonylation of Epoxides and Its Application

摘要

Carbonylation of epoxides catalyzed by cobalt complexes was investigated.A wide range of epoxides were efficiently converted to protected aldols by hydroformylation-acetalization using Co_2(CO)_8 as catalyst in trimethyl orthoformate.When terminal epoxides were used as substrates,a formyl group was selectively incorporated into the less hindered epoxide carbon.Thus,the hydroformylation-acetalization of enantiopure terminal epoxide gave the optically active product with retention of the configuration.Alternating copolymerization of epoxide and CO was also investigated by using cobalt catalysts.In the copolymerization of propylene oxide and CO,NaCo(CO)_4/amine catalyst system selectively gave oligo(3-hydro xybutyrate)s bearing a crotonate-end group which may be used as macromonomer,whereas the use of Co_2(CO)_8 gave oligoesters containing smaller amount of crotonate-end group.