Protodeboronation of thiophenboronic acids

Abstract

The relative rates of protodeboronation of benzene-, thiophen-2-, and thiophen-3-boronic acids at 70° determined by an extrapolation procedure, are 1 : 7.1 x 103 : 8.5 x 105. The relative reactivity for 2-substitution thus exceeds that found for any other electrophilic substitution of thiophen.