Novel Use of Organotin Compounds by Using Higher Coordinating Method.

本研究涉及有机锡烯醇酸盐和有机锡氢化物的新的合成用途，其中锡化合物与Lewis碱的络合作用起到了重要作用。锡烯醇酸盐与α-卤代酮的反应。据报道，锡烯醇酸盐与羰基上的α-卤代酮反应生成卤代醇或环氧乙烷环。相反，我们发现，在这个反应体系中加入膦氧化物等配位化合物，可以提供完全可逆的化学选择性。也就是说，锡烯醇酸盐与α-卤代酮的卤化基团发生了偶联反应。更高配位的锡烯醇酸盐的形成对这种不寻常的反应起到了重要作用。用核磁共振波谱检测到了这种高阶物种。此外，除了化学选择性，最近的研究表明，立体选择性的控制是通过使用呈现的更高配位的锡物种来建立的。较高配位氢化锡还原α-烷氧基酮。与使用自由基法的传统方法不同，锡氢化物通过与Lewis碱络合来使用有效的氢化物给体。也就是说，这种更高配位的方法在α-烷氧基酮的还原中提供了立体选择性的合成烷氧基醇。这些结果可以用费尔金模型来解释。此外，最近我们还认识到了α，β-环氧酮反应中的立体选择性反应。

This study deals with novel synthetic use of organotin enolates and organotin hydrides, in which complexation of tin compounds with Lewis bases played an important role.1. The reaction of tin enolates with alpha-haloketones. Tin enolates have been reported to react with alpha-haloketones at the carbonyl group to afford halohydrins or oxirane ring. In contrast, We have found the addition of coordinating compounds such as phosphine oxides to this reaction system afforded complete reversed chemoselectivity. Namely, the coupling reaction of tin enolates with halide group of alpha-haloketones took place. The formation of higher coordinated tin enolates played an important role for this unusual reactivity. This higher order species were detected by NMR spectra. Moreover, in addition of chemoselectivity, recent study revealed that control of stereoselectivity was established by using presented higher coordinated tin species.2. Reduction of alpha-alkoxyketones with higher coordinated tin hydrides. In contrast to the conventional use using radical method, tin hydrides was revealed to employ efficient hydride donors by complexation with Lewis bases. Namely, this higher coordinating method afforded syn-alkoxy alcohols stereoselectively in the reduction of alpha-alkoxyketones. These results could be explained in terms of Felkin model. Moreover, recently, we have also recognized the stereoselective reaction in the reaction of alpha,beta-Epoxyketones.