Key points are not available for this paper at this time.
The chiral bicyclic triazolium salt 1 is currently the most efficient precatalyst for the asymmetric benzoin condensation. The substituted acyloins 3 are obtained in moderate to good yields and with very good enantiomeric excesses from the corresponding aldehydes 2. The high asymmetric induction is presumably based on the conformational rigidity of the bicyclic nucleophilic carbene catalyst and on the steric hindrance of the tert-butyl group in the Breslow intermediate.
Enders et al. (Fri,) studied this question.