Palladium Catalyzed C-H Arylation Of Aryl Sulfonamides And Copper Catalyed C-N Bond Cleavage

In this thesis,we mainly investigated the palladium catalyzed C-H bond arylation of aryl sulfonyl aminoacids;a novel method for the synthesis of biaryl sulfonamide derivatives has been developed.The related reaction mechanism was explored.At the same time,we realize copper catalyzed C-N bond cleavage of aryl sulfonamidate acid,providing a new way to synthsis primary aryl sulfonamides.This thesis consistes of two parts:(1)Palladium-catalyzed ortho C-H arylation of aryl sulfonamidesAn efficient method for the synthesis of biaryl sulfonamide derivatives by using aryl sulfonamides and aryl iodides as substrates has been developed via palladium(II)-catalyzed C-H bond activation.The protocol proceeded efficiently in water;high yields were achieved.The reaction shows good functional group compatibility and proceeds in a highly selective manner at the ortho position of arenes connected to sulfonamide sulfur atoms.Mechanistic studies show that the present bidentate directing group is essential for promoting ortho C-H bond activation of arenes connected to sulfonamide sulfur atoms,and the palladation process is reversible and not involved in the turnover-limiting step.Finally,a plausible reaction mechanism is proposed.(2)Copper-catalyzed C-N bond cleavage of aryl sulfonamino acidsInitially,we realized copper catalyzed C-N bond cleavage of sulfonamino acid in present of copper oxide as catalyst,in DMSO at 100? for 8h.The present protocol provides an efficient method for the synthesis of primary aryl sulfonamides in excellent yields.Then,we have developed a straightforward route to the synthesis of primary biaryl sulfonamides via palladium(II)/copper(I)-catalyzed sequential C-H arylation and oxidative C-N bond cleavage of aryl sulfonamino acids.In present protocol,the first step for C-H bond arylation reaction was conducted well in present for Pd(OAc)2 and NaOAc,in CH3 CN at 100? for 12 h.The amino acid moiety could be sequentially removed in one-pot reaction by adding CuI as the catalyst and air as a sole oxidant for further 8h.The mechanic study was explored,and a plausible reaction mechanism is proposed.Initially,the Cu-catalyzed oxidative decarbonylation reactions generate the corresponding iminium intermediate.Secondly,the imine intermediate is delivered after deprotonation.Finally,the imine is hydrolyzed to afford the primary aryl sulfonamide and aldehyde.