Tetrahydroxydiboron, Bis-Boric Acid, BBA, B2(OH)4
Tetrahydroxydiboron is a reducing agent, that for example slowly produces hydrogen gas in water.
A rhodium-catalyzed transfer hydrogenation of functionalized arenes in the presence of tetrahydroxydiboron offers good functional group tolerance, operational simplicity and controllable chemoselectivity. The general applicability of this procedure is demonstrated by the selective hydrogenation of a range of arenes, including functionalized benzenes, biphenyls, and polyaromatics.
Y. Wang, Z. Chang, Y. Hu, X. Lin, X. Dou, Org. Lett., 2021, 23, 1910-1914.
A metal-free reduction of nitro aromatics is mediated by tetrahydroxydiboron under mild conditions in water as solvent to provide various aromatic amines with good functional group tolerance and in good yields.
D. Chen, Y. Zhou, H. Zhou, S. Liu, Q. Liu, K. Zhang, Y. Uozumi, Synthesis, 2018, 50, 1765-1768.
A copper-catalyzed one-pot reaction of 2-nitrobenzonitriles and various carbonyl compounds in the presence of diboronic acid as a reductant provides 2,3-dihydroquinazolin-4(1H)-ones with good functional-group tolerance in good yields under mild conditions.
Q. Liu, Y. Sui, Y. Zhang, K. Zhang, Y. Chen, H. Zhou, Synlett, 2020, 31, 275-279.