Copper-mediated reactions of Boron-Element-Compounds: Mechanistic Investigations and Catalytic Applications

铜催化的亲核硅基从元素-硼-化合物到有机底物的转移反应是目前研究较多的一组反应。这些反应是合成含硅积木的通用工具。最近，几个小组报道了各种铜催化的硅部分从硼酸衍生物转移到亲电体上的反应，如醛、α、β-不饱和羰基化合物、烯丙基氯化物等。尽管这些反应相似，但令人惊讶的是使用了不同的催化体系。所使用的催化体系可以正式地分为三类：NHC-铜络合物、磷-铜络合物和铜(I)氰化物体系。本文旨在继续NHC-铜体系的机理研究，并将其扩展到铜(I)氰化物体系，所获得的机理认识将被用于开发新型NHC-铜配合物催化14族元素硼元素化合物的转化。主要的焦点将是将硅基转移反应扩展到新的有机底物，特别是活性较低的羰基化合物(如酮、酯)，并将该方法的范围扩展到其他合成上感兴趣的、以前没有使用过的硼元素化合物。尤其是碳的硼元素化合物具有很大的合成价值。碳-元素偶联反应(C-C、C-Si、C-Sn等)的研究进展应该为合成化学家工具箱提供一个有价值的扩展。

Copper-catalysed transfer reaction of nucleophilic Silicon moieties from element-boron-compounds onto organic substrates are a currently intensively studied group of reactions. These reactions are versatile tools in the synthesis of silicon-containing building-blocks. Recently, several groups reported various copper-catalysed transfer reaction of silicon moieties from boronic acid derivatives onto electrophiles such as aldehydes, alpha, beta-unsaturated carbonyl compounds, allyl chlorids, etc. Despite the similarity of these reactions surprisingly different catalytic-systems have been used. The used catalytic systems may be formally classified into three groups: NHC-copper complexes, phosphan-copper complexes and copper(I) cyanide based systems. Only for the NHC-copper system first mechanistic studies have been reported recently by the applicant.This proposal aims to continue the mechanistic investigation on the NHC-copper systems and moreover extend the mechanistic investigations to the copper(I) cyanide based systems.The gained mechanistic understanding will be used to develop novel NHC-copper complex catalysed transformation of boron-element compounds of group 14. elements. The main focus will be on the extension of the silyl-group transfer reaction to new organic substrates, especially less activated carbonyl compounds (e. g. ketones, esters) and the extension of the scope of the method to other synthetically interesting, previously not used, boron-element compounds. Especially boron-element compounds of carbon are of great synthetic interest. The development of such carbon-element coupling reactions (C-C, C-Si, C-Sn, etc.) should provide a valuable extension to the synthetic chemists tool box.