The enantioselective benzoin condensation promoted by chiral triazolium precatalysts: stereochemical control via hydrogen bonding.
The design of a new class of triazolium ion precatalysts incorporating protic substituents is described. These materials promote the enantioselective benzoin condensation of a range of aromatic aldehydes (1-62% ee). Catalyst evaluation studies strongly support the involvement of hydrogen bond donation by the catalyst in the stereocentre-forming step of the catalytic cycle.
O'Toole
Sarah E
SE
Centre for Synthesis and Chemical Biology, School of Chemistry, University of Dublin, Trinity College, Dublin 2, Ireland.
Connon
Stephen J
SJ