A Simple Approach To C3-ethoxycarbonylmethylation Of Thiophenes/Furans With Diethyl Bromomalonate

Thiophene/furan derivatives are widely used in medicals science and materials science because of good medicinal value,biological activities,optical and electronic properties.Malonate esters have been proven to be an important intermediate for synthetic drugs,liquid crystal materials,amino acids,insect alarm pheromones,and antibacterial derivatives,etc.The existing methods of C3malonated thiophenes/furans have disadvantages such as severe reaction conditions,troublesome pre-preparation and isolation of the substrate.Considering the advantages of visible light-induced synthetic strategy,the development of methods to directly prepare C3-malonated thiophenes/furans under visible-light irradiation is highly important and attractive.Herein,we developed a mild and efficient visible light-induced C-3 functionalization reaction of thiophene/furan compounds with diethyl bromomalonate.The main research contents are as follows:1.A method to produce a series of C3-malonated products was developed via a visible-light-induced reaction of 2-substituted thiophenes/furans with diethyl bromomalonate.This method exhibits broad substrate scope,good functional group tolerance and high yields(Scheme 1).#12 Scheme 12.The results of the control experiments,cyclic voltammetry and spectrophotometric studies indicated that the studied reaction might proceed via a radical process.The photocatalyst played the role of the reductant for diethyl bromomalonate.