Heating of 3,3,4,4-tetrabromo-1,2-bis(diphenylmethylene)cyclobutane in dichloroacetic acid afforded bridgehead olefin, 7-bromo-1,4,8-triphenyl-2,3-benzobicyclo[3.3.0]octa-2,4,7-trien-6-one, and spiroketone, 2-bromo-2′,3-diphenylspiro[1H-indene-1,1′(4′H)-naphthalen]-4′-one (13). Mechanism of the reaction was discussed. X-Ray structural study of the spiroketone 13 was also reported.
3,3,4,4-四溴-1,2-双(二苯基亚甲基)环丁烷在二氯乙酸中加热得到桥头烯烃,7-溴-1,4,8-三苯基-2,3-苯并双环[3.3.0]八-2,4,7-trien-6-one,和螺酮,2-bromo-2',3-diphenylspiro[1H-indene-1,1'(4'H)-naphthalen]-4'-one ( 13)。讨论了反应机理。还报道了螺酮 13 的 X 射线结构研究。