Pure Appl. Chem., 2003, Vol. 75, No. 9, pp. 1249-1253
doi:10.1351/pac200375091249
New asymmetric syntheses with boronic esters and fluoroboranes*
Donald S.Matteson
Department of Chemistry, Washington State University, Pullman, WA 99164-4630, USA
Abstract:
Efficient cleavage of sterically hindered boronic esters of asymmetric diols to recover both the diol and a more reactive borane derivative has been a challenging problem. A remarkable borosilicate glass-catalyzed cleavage with thionyl chloride and imidazole proved less useful than hoped for. Potassium bifluoride converts boronic esters to diols and alkyltrifluoroborates. These with chlorosilanes yield alkyldifluoroboranes, which with alkyl azides form secondary amines in high enantiopurity.
*Lecture presented at the XIth International Meeting on Boron Chemistry (IMEBORON XI), Moscow, Russia, 28 July - 2 August 2002. Other presentations are published in this issue, pp. 1157-1355.