The kinetics and mechanism of the reaction of triarylphosphines with 7,7,8,8-tetracyanoquinodimethane and tetracyanoethylene
作者:M. P. Naan、R. L. Powell、C. D. Hall
DOI:10.1039/j29710001683
日期:——
tetracyanoethylene (TCNE) and triarylphosphine give tetracyanoethane and the phosphine oxide. Using an optically active phosphine, the oxide recovered from both reactions is completely racemic. Kinetic data on the reaction of TCNQ with triarylphosphines are reported and by consideration of the order, deuterium isotope effect and activation parameters coupled with the stereochemical evidence it is proposed that the
三芳基膦在水和催化量的盐酸存在下,与氯仿,乙腈或乙腈-苯中的7,7,8,8-四氰基喹二甲烷(TCNQ)反应,得到定量的1,4-双-(二氰基甲基)苯和三芳基氧化膦。类似地,在乙腈中,在含水酸的存在下,四氰基乙烯(TCNE)和三芳基膦生成四氰基乙烷和氧化膦。使用光学活性的膦,从两个反应中回收的氧化物都是完全外消旋的。报道了TCNQ与三芳基膦反应的动力学数据,并考虑顺序,氘同位素效应和活化参数以及立体化学证据,提出该反应通过through自由基阳离子中间体进行。速率与取代膦的σ取代基参数的Hammett相关性得出ρ值为–3·2。还讨论了三芳基膦与TCNQ和TCNE在绝对非质子介质中的反应。