1, 3-双磷(膦)酰基丙烯类化合物的^1H、^3^1P NMR研究

本文报道了标题类化合物中十个化合物的^1H和^3^1PNMR的研究结果。其中分别运用了2DJ分解谱以及异核COSY谱等多种技术,解析了它们的^1H和^3^1P图谱,从而证实了合成反应的区域选择性和立体选择性。文章中,讨论了手性中心或其它因素而表现出的不等性;讨论了影响δ~P和J~p~H数值的各种因素:还报道了比较少见的^3^1P-^3^1P之间的远程偶合。其中,顺式产物的^4J~P~P数值(约9Hz)大于反式产物的^4J~P~P(约7Hz)。

^1H and ^3^1P NMR studies of 1, 3-diphosphorylpropenes

The ^1H and ^3^1P NMR spectra of 1, 3-diphosphorylpropenes prepared by a new reaction were studied. Homo 2DJ and hetero 2D COSY have been employed in distinguishing J(HH) and J(PH), and the signals of the isomeric mixtures. ^3J(HH) of vinyl groups confirmed the regioselectivity, showing the trans form to be the main products (～ 95%). In compounds except 1, 2 and 7, different positions of double bond give rise to the existence of two isomers, A and B, with the latter ～10% in excess. In 1 and 2, four identical R groups were divided in to two groups because of the presence of a double bond, and the same groups attached to the different achiral P atom are non- equivalent as well. These are confirmed by the spectra of hydrogenation products. However, δ~p of the two P atoms show different behavior with -P(O)Ph(OR) at the lowest field. ^4J(PP) among these compounds were obtained, J~c~i~s(9Hz)>J~t~r~a~n~s(7Hz). The reduced values from those of hydrogenation products confirm the enhancement of P-P coupling by π electrons.