Studies On Free-Radical Promoted C-Si Bond Formation Via Selective Si-H Functionalization

Organosilicon compounds find wide applications in material science,pharmaceuticals and bioactive compounds.The natural supply of silicon is very abundant on earth,which is only less than oxygen.However,efficient strategies for C-Si bond construction have not been well-developed in synthetic organic chemistry.In recent years,studies on exploring efficient synthetic approaches to these compounds have gained much attention,and lots of efforts have been made in this area.In this essay,we first summarized the recent advances in this field.Then several investigations on free-radical-promoted selective activation of Si-H bond to form C-Si were introduced in details which were found by our group.Finally we summed up the developments in this area and its outlook.This thesis mainly contains the following four sections.In the first chapter,recent developments of construction C-Si bond were summarized,and this chapter can be devided into two parts,(1)transition-metal-catalyzed C–H silylation;(2)free-radical strategies for C–Si construction through selective C–H/Si–H functionalization.Chapter 2 demonstrated a novel and efficient silylarylation of activated alkenes via a free radical addition/cyclization cascade process,which allowed a convinent access to silylated oxindoles and its derivatives through selective functionalization of Si-H/C-H Bonds.In the third chapter,a stereospecific decarboxylative silylation of ?,?-unsaturated acids with silanes was introduced.A variety of silylated styrenes and phenylacetylenes could be facilly obtained by using cinnamic acids with hydrosilanes.A elegantly designed free radical addition/elimination strategy enables the products to be stereospecific.In Chapter 4,we depicted a free-radical cascade trifluoromethylation/cyclization of N-arylmethacrylamides with enynes by using NaSO2CF3 and I2O5.It could provide an efficient approach to trifluorinated heterocycles.Finally,we summarized the developments of free-radical-promoted C–Si formation through selective Si-H functionalization.Also we proposed the outlook of this field in the end of this thesis.