Catalytic Addition of Homoenolates to Imines - The Homo-Mannich Reaction

For the first time, homo-Mannich reactions with unmasked homoenolates have been achieved by adding homoenolate precursor 1 and imines 5. The key to this reaction is the right choice of the Lewis acids - Cu(OTf)2 proved to be most suitable for preparing the homoenolate and activation of the imine. An asymmetric catalytic version of this reaction is provided by using chiral, non-racemic phenyl-derived bisoxazolidine as ligand for the Lewis acid.