Synthesis 2023; 55(10): 1570-1576
DOI: 10.1055/a-1988-5943
paper

Base-Mediated Direct Carboxylation of Heteroarenes with CO2

Cheng Y. Zhang
,
Yan J. Chen
,
Ya Y. Wang
,
Xin H. Peng


Abstract

A base medium system, generated from a synergistic reaction between Cs2CO3 and t-BuOK, has been used for the direct carboxylation of imidazoles with CO2 in good yield. Oxygen- and thia-heterocyclic arenes also undergo the carboxylation with CO2 with the same reactivity. Density functional theory calculations show that construction of t-BuOCs in situ is an endothermic process of 38.31 kJ/mol. t-BuOCs can promote the deprotonation of substrates by forming an active C–Cs bond via a rather low HOMO (t-BuOCs)–LUMO (imidazole) gap of 0.28 eV, which favors the electrophilic insertion of CO2 by releasing 94.13 kJ/mol of heat.

Supporting Information



Publication History

Received: 27 October 2022

Accepted after revision: 28 November 2022

Accepted Manuscript online:
28 November 2022

Article published online:
18 January 2023

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