Catalytic dynamic kinetic resolutions with N-heterocyclic carbenes: asymmetric synthesis of highly substituted ß-lactones.

ABSTRACT

New DKR type An N-heterocyclic carbene (NHC)-catalyzed dynamic kinetic resolution of racemic α-substituted ß-keto esters has been developed. This method relies on the epimerization of an NHC-enol intermediate before subsequent aldol/acylation events. Highly substituted ß-lactones are produced in good yield with good to excellent selectivities (see scheme).