Process for preparing 5-(2-bromoethylidene)-2(3H)-4a-methyl-4,4a,5,6,7,8-hexahydronaphthalene-2-one and 5-ethenyl-2(3H)-4a-methyl-4,4a,7,8-tetrahydronaphthalene-2-one therefrom by dehydrobromination.

摘要

5-Ethenyl-4,4a,7,8-tetrahydro-4a-methyl-2(3H)-naphthalenone, an intermediate useful in the total synthesis of steroids, is prepared by dehydrohalogenation of 5-(2-bromo-ethylidene)-2(3H)-4a-methyl-4,4a,5,6,7,8-hexahy- dronaphthalen-2-one by a pyrolytic procedure or by means of dehydrohalogenating agents, for example, a mixture of lithium bromide and lithium carbonate.