Copper-promoted Esterification Of Buntes Salts And Phenols

As a kind of important chemical raw materials,carboxylates are widely used as spices,solvents,plasticizers,organic synthesis intermediates as well as in the fields of polymer,pharmaceutical and liquid crystal materials.Therefore,it is still a challenge to develop a simple,clean and environmentally benign route to synthesize diphenylcarboxylate derivatives via esterification reaction.In recent years,various sulfur-containing reagents such as sulfonyl hydrazides,sulfonamides,sulfonyl chlorides,sulfonates,thioethers,thiols(phenols),Buntes salts and so on,were applied to a large number of C-S bond formation reactions.However,the cleavage of C-S bond of Buntes salt for esterification remains as an undeveloped area.In this paper,the synthetic methods of esterification reaction were summarized firstly.Then,the application of Buntes salt and disulfide in C-S bond coupling reations was briefly reviewed.Finally,a cupper-promoted esterification of Buntes salt with phenols was described in this thesis.A series of diphenylcarboxylate derivatives were obtained by using imidazole as the ligand,sodium carbonate as the base,DMSO as solvent at 100 oC for 7 h.This reaction tolerates many functional groups,providing the corresponding compounds with moderate to excellent yields(Sche me 1).The obtained compounds were identified by 1H NMR,13 C NMR.A possible mechanism was also proposed according to the control experiment and the trapped intermediate.