Hypoboric Acid Catecholate (HAC) Catalysis for Stereoselective Decarboxylative Borylation of Redox-Active Esters
Year: 2026
Type: preprint
Abstract: The Hypoboric Acid Catecholate (HAC) is a new class of diboron reagent bearing a borylcatecholato and a boronic acid moiety. Herein, we demonstrate that HACs can also be expontaneously formed in situ from collections of catechols and hypoboric acid. These HACs catalyze the decarboxylative borylation of redox-active esters, providing superior reactivity and selectivity. Equilibrium and kinetic NMR experiments indicate that the catalytic turnover is enabled by the high affinity of catechols for hypoboric acid and their low affinity for boronic acids that is uncovered herein. The catalytic system operates in mild conditions and is robust towards air and moisture, demonstrating its utility in the synthesis of important medicinally-relevant boronates. The enhanced selectivity is sourced in the regioselective radical capture by HAC intermediates at their customized borylcatecholato moiety, which can easily be stereoelectronically tailored for specific applications. These features of the catalytic approach with unsymmetrical HACs presented herein contrast with current state-of-the-art methods based on stoichiometric symmetrical diboron reagents.
Source: ChemRxiv
Institutions: Stockholm University, Universitat de València
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7220469349