Copper-Catalyzed Divergent Transformations Of Terminal Alkynes With Silaboronate Reagent

Organosilicon compounds are a kind of important synthons in the field of synthetic chemistry.Due to the unique reactivity of C-Si bond,organosilicon compounds have many applications of pharmaceutical chemistry,material chemistry,and organic synthesis chemistry.Compared with other organometallic reagents,organosilicon compounds are usually air stable and easy to handle,which makes them as ideal building block to synthesize complex compounds.Therefore,it is important to develop easier and more efficient methods to synthesize organosilicon compounds.In this dissertation,we developed a series of methods for the preparation of organosilicon compounds using alkynes as starting materials and cheap copper as catalysts to catalyze the formation of new C-Si bonds with silylborane reagents.This dissertation is divided into four parts.First of all,transition-metal catalyzed silylation/functionalization of alkynes well be reviewed.The latter three parts mainly discuss the copper-catalyzed diversified reaction of terminal alkynes and silylborane reagents.The following is a brief introduction to this dissertation:1.Copper-catalyzed silaboration of alkynes:The regio-and stereoselective silaboration of alkynes catalyzed by copper,which are controlled by ligands,have been studied.In aprotic solvents,a series of multi-substituted alkenes were synthesized by using copper-catalyzed silylborane for cis-addition of alkynes.By fine-tuning the types of copper catalysts and phosphine ligands in the reaction conditions,the controllable regioselective silaboration reaction was achieved.This approach has excellent selectivity and high yield,and provides an economical and practical method for synthesizing silyl and boryl disubstituted alkenes.We also used the template product to synthesize two stereoselective multi-substituted conjugated enyne fragments.Besides,under the catalysis of CuTc/PCy3,the 1,2-dialkylenecyclopentanes were prepared for the first time by the silaboration/cyclization reaction of silylborane to 1,6-diyne or 1,7-diyne.2.Synthesis of gem-diborylated vinylsilanes prepared by copper-catalyzed silaboration of terminal alkynes:Under the catalysis systems of CuOAc/PCpy3,the 1,1,2-trifunctionalization of terminal alkynes with silylborane was studied.A series of gem-diborylated vinylsilane derivatives were prepared with medium to good yields.The products are potential inhibitors of matrix metallo-proteinase(MMP-2).These products can be further derivatized to prepare stereospecific tetra-substituted olefin compounds.3.Copper-catalyzed chemoselective protosilylation/cyclization of 2,2'-diethynylbiaryl derivatives:The copper catalyzed chemoselectivity protosilylation/cyclization of 2,2'-diethynylbiaryl derivatives with silylborane was studied.Under different copper catalyst systems,the corresponding cyclobuta[l]phenanthrene derivatives,silyl-substituted exocyclic diene products and bis((silyl)methyl)phenanthrene derivatives were chemoselectively formed with high efficiency.This method can construct silyl-substituted complex molecules in one step under mild conditions.At the same time,the derivatization of cyclobuta[l]phenanthrene derivatives and silyl-substituted exocyclic diene products show that they are highly effective reagents for the synthesis of complex structure compounds.