Novel Use of Organotin Compounds by Using Higher Coordinating Method.

本研究探讨了有机锡烯醇酸酯和有机锡氢化物的新合成用途，其中锡化合物与路易斯碱的络合作用起着重要作用。锡与-卤酮发生烯化反应。有报道称，锡烯醇化物在羰基上与-卤酮反应生成卤代醇或氧环。相反，我们发现配位化合物（如氧化膦）加入到该反应体系中可以提供完全的反向化学选择性。即，锡烯醇化物与α -卤酮的卤化物基团发生偶联反应。高配位锡烯醇化物的形成对这种不寻常的反应性起了重要作用。这些高阶物质通过核磁共振光谱被检测到。此外，除了化学选择性外，最近的研究表明，利用所提出的高配位锡种可以控制立体选择性。高配位锡氢化物还原α -烷氧酮。与传统的自由基法相比，锡氢化物通过与路易斯碱络合可以有效地利用氢化物供体。也就是说，这种高级配位方法在α -烷氧酮的还原中提供了立体选择性的顺烷氧醇。这些结果可以用Felkin模型来解释。此外，最近我们还发现了在α， β -环氧酮的反应中存在立体选择反应。

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.