Carbene chemistry. Part IV. Carbene intermediates in pyrolyses of trifluoro(polyfluoroethyl)silanes, trichloro(polyfluoroethyl)silanes, and trichloro(trichloromethyl)silane
作者:William I. Bevan、Robert N. Haszeldine
DOI:10.1039/dt9740002509
日期:——
an olefin; in the former case the carbene has been trapped with isobutene. Similarly pyrolysis of a mixture of trichloro(trichloromethyl) silane and cyclohexene at 250–260 °C gives 7,7-dichloronorcarane via the intermediacy of dichlorocarbene. Thermal decomposition of the silanes CH2F·CF2·SiCl3 and CHF2·CF2SiCl3 at 225 °C affords, in each case, a mixture of chlorofluorosilanes and three olefins, two
硅烷CH 2 F·CF 2 ·SiF 3和CFCl 2 ·CF 2 ·SiF 3在140℃通过α消除四氟化硅而发生热分解,得到重排为烯烃的卡宾;在前一种情况下,卡宾已被异丁烯捕获。同样,在250–260°C的温度下,三氯(三氯甲基)硅烷和环己烯的混合物会热解,从而通过二氯卡宾的中间体生成7,7-二氯正烷。硅烷CH 2 F·CF 2 ·SiCl 3和CHF 2 ·CF 2 SiCl 3的热分解在每种情况下,在225℃下,得到氯氟硅烷和三种烯烃的混合物,其中两种含有氯。不含氯的烯烃是通过三氯氟硅烷的α消除反应和重整生成的卡宾而形成的。含氯烯烃的形成涉及将硅上的氯交换为α-碳原子上的氟,从而得到重排的硅烷R·CFCl·SiCl 2 F和R·CCl 2 ·SiClF 2(R = CH 2 F或CHF 2),然后分别通过α消除二氯二氟硅烷和β消除氯三氟硅烷进行分解。