USE OF PROCHIRAL PHOSPHAALKENE COMPLEXES IN THE SYNTHESIS OF OPTICALLY-ACTIVE PHOSPHINES
USE OF PROCHIRAL PHOSPHAALKENE COMPLEXES IN THE SYNTHESIS OF OPTICALLY-ACTIVE PHOSPHINES
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DOI：
10.1021/ja00027a034
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发表时间：
1992-01-01
影响因子：
15
通讯作者：
MATHEY, F
中科院分区：
文献类型：
--
作者：
DEVAUMAS, R;MARINETTI, A;MATHEY, F
以“磷酸-维提格”试剂、[MenP(H)- p -(O) (OR)2]M(CO)5 （M = Mo， W）和几种醛为原料制备了l -薄荷基磷酸烯烃配合物。它们在RhL2+催化剂上的催化加氢和与环戊二烯的[2 + 4]环加成均具有完全的非对映选择性。这种磷酸烯烃配合物的分子模型表明，存在一种优选构象，使l -薄荷基的异丙基取代基与配合基和磷酸乙烯基C-H键的联合相互作用最小化。在这个构象中，只有磷酸烯烃的硅面对进入的试剂是自由的。两种配合物的x射线晶体结构分析表明，与环戊二烯的氢化和[2 + 4]环加成都选择性地发生在这一表面。设计了将[MenPH2]Mo(CO)5转化为光学纯磷化氢的两步法。在第一步中，将原膦配合物磷酸化，得到的磷- wittig试剂与醛反应，形成的磷烯烃配合物被环戊二烯捕获。钼配合物的解合作用是用二磷加热进行的。由此制备了光学纯的2- l-甲基-2-磷酸-5-降冰片烯。
Prochiral L-Menthyl phosphaalkene complexes were prepared from ''phospha-Wittig'' reagents, [MenP(H)-P-(O) (OR)2]M(CO)5 (M = Mo, W), and several aldehydes. Their catalytic hydrogenation using RhL2+ catalysts and their [2 + 4] cycloaddition with cyclopentadiene proceeded with full diastereoselectivity. A molecular model of such a phosphaalkene complex showed that a preferred conformation exists that minimizes the combined interactions of the isopropyl substituent of the L-menthyl group with the complexing group and the phosphavinylic C-H bond. In this conformation, only the si face of the phosphaalkene is free for the incoming reagents. Both hydrogenation and [2 + 4] cycloaddition with cyclopentadiene selectively take place on this face as demonstrated by the X-ray crystal structure analysis of two of the resulting complexes. A two-step procedure was devised for the conversion of [MenPH2]Mo(CO)5 into optically pure phosphines. In the first step, the primary phosphine complex was phosphorylated, the resulting phospha-Wittig reagent was allowed to react with an aldehyde, and the phosphaalkene complex thus formed was trapped by cyclopentadiene. The decomplexation of the resulting molybdenum complex was carried out by heating with diphos. An optically pure 2-L-menthyl-2-phospha-5-norbornene was thus prepared.