Cu-catalyzed carboxylation of organoboronic acid pinacol esters with CO2

Abstract

Chemical fixation of CO₂ has received much attention. In particular, catalytic C–C bond formation with CO₂ giving carboxylic acids is of great significance. Among the CO₂ fixation methods, multiple carboxylation is one of the challenging subjects. Here we investigated the Cu-catalyzed carboxylation of a variety of boronic acid pinacol esters (C(sp²)–, C(sp³)–, and C(sp)–B compounds) with CO₂, which efficiently provided the corresponding products, including aryl, alkenyl, alkyl, and alkynyl carboxylic acids. This carboxylation was also applicable to multiple CO₂ fixation giving di- and tri-carboxylic acids under robust reaction conditions (totally 29 examples).