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Boric acid as a precatalyst for BH3-catalyzed hydroboration
Julien Légaré Lavergne1, Hoang-Minh To1, Frédéric-Georges Fontaine1
1Département de Chimie, Université Laval 1045 Avenue de la Médecine Québec G1V 0A6 Québec Canada frederic.fontaine@chm.ulaval.ca.
Abstract:
We report that boric acid, BO3H3, is a good precatalyst for the BH3-catalyzed hydroboration of esters using pinacolborane as a borylation agent. Using microwave irradiation as an energy source, we demonstrated that a dozen esters were converted into the corresponding boronate ethers in good yields. It was also possible to use boric acid as a precatalyst to reduce carbonates and alkynes. Considering the hazardous and pyrophoric nature of BH3 solutions, boric acid proves to be a safe and green precatalyst for the metal-free reduction of unsaturated species.
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