Reaction of 2,4-Difunctional Esters of 5-tert-Butylfuran-3-carboxylic Acid with Nucleophilic Reagents

Article abstract of DOI:10.1023/A:1024962020862

Ethyl 5-tert-butyl-4-(chloromethyl)-2-methylfuran-3-carboxylate was brominated with N-bromosuccinimide to obtain the corresponding 2-bromomethyl derivative. The latter is selectively phosphorylated with trimethyl and triethyl phosphites by the bromomethyl group. The resulting [4-(chloromethyl) furyl]methylphosphonates in the presence of secondary amines and sodium butanethiolate behave as alkylating agents, while sodium phenolate causes their decomposition. 4-Acetoxymethyl- and 4-phenoxymethyl derivatives of the starting product are also selectively brominated with N-bromosuccinimide by the 2-methyl group. The first of the 2-(bromomethyl)furans formed is smoothly phosphorylated with trimethyl phosphite, while the second one under the action of triethyl phosphite gives a mixture of phosphorylation and debromination products. In all the cases, an additional electron-acceptor group in position 4 of alkyl 2-(bromomethyl)-5-tert-butylfuran-3-carboxylate considerably accelerates the Arbuzov reaction.