Reactivity of triethyl phosphite with tetrachloromethane : electron transfer versus ionic substitution on “positive” halogen
作者:Salem Bakkas、Michel Julliard、Michel Chanon
DOI:10.1016/s0040-4020(01)89983-x
日期:1987.1
the first therefore suggests a radical mechanism but not the second.However in this particular case even the results obtained with the tris(cyclopropylnethyl) phosphite may be rationalized also by an ionic mechanism. For the photostimulated reaction [1] , the overall quantum yield is 0.1. The electrochemical oxidation of 1 with added CCI4 does not account for a radical chain process as the main pathway
从机理的角度研究了亚磷酸三乙酯(1)与四氯甲烷(2)的反应[1]。1在80°C下与2反应形成三乙基三氯甲烷膦酸酯(03)(85-90%的收率)和氯乙烷(4)(80%的收率)。若干结果暗示了自由基链机制(如S RN1)。三氯甲基自由基被2,6-二叔丁基-4-甲酚(BHT)捕获,反应可以通过UV辐射(254 nm)引发,并且在1和2之间形成电荷转移络合物(CTC);此外,该反应被7,7',8,8'四氰基喹二甲烷(TCNQ)抑制。在这些反应中,将亚磷酸三(环丙基甲基)酯(12a)和亚磷酸三(1-己烯-6基)酯(7a)用作潜在的自由基钟。第一个导致3-氯-1-丁烯(17),第二个导致5-氯-1-己烯(11),因此第一个提示了自由基机理,但没有第二个提示。亚磷酸三(环丙基乙基)酯获得的结果也可以通过离子机理来合理化。对于光刺激反应[1],总量子产率为0.1。添加CCI的1的电化学氧化4并未将激进的连