The introduction of an EtO2CCF2- group into lithium enolates of chiral N-acyloxazolidinones with ethyl difluoroiodoacetate mediated by triethylborane proceeds with good diastereomeric excess (86->98% de).
The bromodifluoromethylation of lithium enolates of chiral N-acyloxazolidinones via the insertion of difluorocarbene proceeds with good diastereomeric excess (68–92% de).