Krysiak Jerzy, Lyon Céline, Baceiredo Antoine, Gornitzka Heinz, Mikolajczyk Marian, Bertrand Guy
Laboratoire Hétérochimie Fondamentale et Appliquée, UMR 5069, Université Paul Sabatier, 118, route de Narbonne, 31062 Toulouse Cedex 04, France.
Chemistry. 2004 Apr 19;10(8):1982-6. doi: 10.1002/chem.200305722.
The stability of phosphino(trimethylsilyl)carbenes bearing cyclic diamino substituents on phosphorus is strongly dependent on the steric hindrance of the nitrogen substituents. Phosphinocarbenes 3 and 7, derived from the trans-N,N'-diisopropylcyclohexane-1,2-diamine and N,N'-diisopropyl-1,2-ethanediamine, are not observed; instead the 1,3-diphosphete 4 and a novel six-membered heterocycle 8, which results from the dimerization of 3 and the reaction of 7 with its diazo precursor 6, respectively, have been isolated. In contrast, the phosphino(silyl)carbene 14 derived from N,N'-di-tert-butyl-1,2-ethanediamine has been isolated in high yield. By using the enantiomerically pure (S,S)-, and (R,R)-N,N'-di-tert-butyl-1,2-diphenyl-1,2-ethanediamines, the first optically pure phosphino(sily)carbenes (S,S)-17 and (R,R)-17 have been prepared. They react with methyl acrylate to give the corresponding cyclopropanes (S,S,R,R)-19 and (R,R,S,S)-19 with a total syn diastereoselectivity and an excellent enantioselectivity (de>98 %).
磷上带有环状二氨基取代基的膦基（三甲基硅基）卡宾的稳定性强烈依赖于氮取代基的空间位阻。未观察到由反式-N,N'-二异丙基环己烷-1,2-二胺和N,N'-二异丙基-1,2-乙二胺衍生的膦基卡宾3和7；相反，分别分离出了由3二聚形成的1,3-二磷杂环丁烷4和由7与其重氮前体6反应形成的新型六元杂环8。相比之下，由N,N'-二叔丁基-1,2-乙二胺衍生的膦基（硅基）卡宾14已被高收率分离出来。通过使用对映体纯的（S,S）-和（R,R）-N,N'-二叔丁基-1,2-二苯基-1,2-乙二胺，制备了首个光学纯的膦基（硅基）卡宾（S,S）-17和（R,R）-17。它们与丙烯酸甲酯反应，以完全的顺式非对映选择性和优异的对映选择性（de>98%）得到相应的环丙烷（S,S,R,R）-19和（R,R,S,S）-19。
