Boron-Nitrogen Chemistry

Abstract

8-Quinolineboronic acid, 2-(2-boronophenyl)-benzimidazole, and 2-(2-boronobenzyl)benzimidazole were found to catalyze a reaction of chloroethanol with hydroxylic compounds (water or alcohols) in the presence of collidine. 2-(2-Pyridylethynyl)benzeneboronic acid, in which the borono and amine functional groups are farther separated than in these compounds, did not exhibit comparable activity; however, it underwent isomerization in chloroethanol to a substance which was an active catalyst. The unusual reactivity of these boron-nitrogen compounds is attributed to cooperation of the boronic acid and amine groups in acting on the hydroxylic substrates. Spectral data relevant to the structures of the compounds are presented and mechanistic pathways for the catalytic reactions are discussed.