One-Pot Synthesis of 2‑(Het)aryl/alkyl-3-cyanobenzofurans from 2‑(2-Bromoaryl)-3-(het)aryl-3-(methylthio)acrylonitriles and Benzyl Carbamate

A one-pot synthesis of 2-(het)­aryl/alkyl-3-cyanobenzofurans
has
been reported. The overall sequence involves base-induced reaction
of 2-(2-bromoaryl)-3-(het)­aryl-3-(methylthio)­acrylonitriles with benzyl
carbamate, generating α-(het)­aroyl-α-(2-bromoaryl)­acetonitriles,
which are in situ subjected to copper-catalyzed intramolecular O-arylation, furnishing the 2-(het)­aryl/alkyl-3-cyanobenzofurans
in high yields. A probable mechanism for the base-induced cleavage
of 2-(2-bromoaryl)-3-(het)­aryl-3-(methylthio)­acrylonitriles to α-(het)­aroyl-α-(2-bromoaryl)­acetonitriles
in the presence of benzyl carbamate has been proposed.