An efficient, regiocontrolled synthesis of 5-aryl-2-carbethoxypyrroles from 3-aryl-3-chloropropeniminium salts

A variety of 3-chloropropeniminium salts react with α-amino acid esters under basic conditions to produce 2-carbethoxy-5-arylpyrroles in a regioselective manner. The overall process represents a short, efficient, and convergent synthesis of 2,5-disubstituted pyrroles, and azomethine ylides or azapentadienyl anions may be involved as intermediates