Diastereoselective Aldol Reaction of Tin Enolate of Cyclohexanone Catalyzed by Metal Triflates

Abstract
The diastereoselective aldol reaction of tributyltin enolate of cyclohexanone with benzaldehyde was studied in the presence of a catalytic amount of various metal triflates. The highest anti selectivity was observed with Pd(OTf)2, while Zn(OTf)2 in THF showed moderate syn selectivity. The use of (S,S)- i Pr-pybox 3 ⋅ Cu(OTf)2 complex as a catalyst preferentially produced the optically active syn aldol adduct with 84% ee.