Carbanionic displacement reactions at phosphorus. Part III. Cyanomethylphosphonate vs. cyanomethylenediphosphonate. Synthesis and solid-state structures
作者:Bogdan Iorga、Louis Ricard、Philippe Savignac
DOI:10.1039/b003371p
日期:——
The results of the carbanionic reaction between acetonitrile and chlorophosphates depend strongly on the nature of the metallating agent (LiTMP, LDA, LiHMDS). According to the nature of the base, the reaction can be directed towards the formation of either cyanomethylphosphonates 3 or cyanomethylenediphosphonates 5. Electrophilic halogenation of lithiated cyanomethylphosphonate 2a leads to the mono-chloro 17, -bromo 18 and -iodo 19 derivatives. Only the monochloro product 17 is stable enough to be isolated in pure form. The structures of cyanobenzylphosphonate 10b, cyanomethylenediphosphonate 5b and its corresponding lithiated carbanion 4b are determined by X-ray crystallography. The polymeric structure, coupled with a wide charge delocalization, without C–Li contacts, is in agreement with the lack of reactivity towards electrophiles.
乙腈与氯膦酸酯之间的负碳阴离子反应结果在很大程度上依赖于金属化试剂的性质(LiTMP, LDA, LiHMDS)。根据碱的性质,反应可以定向生成氰基甲基膦酸酯 3 或氰基亚甲基二膦酸酯 5。锂化的氰基甲基膦酸酯 2a 的亲电卤素化反应会导致单氯 17、单溴 18 和单碘 19 衍生物的生成。只有单氯产品 17 稳定到足以以纯形式分离出来。通过X射线晶体学确定了氰基苄基膦酸酯 10b、氰基亚甲基二膦酸酯 5b 及其相应的锂化负碳阴离子 4b 的结构。聚合结构,以及宽广的电荷去局域化,没有 C–Li 接触,这与缺乏对亲电体反应性的情况是一致的。