Enolates generated from α-bromo esters by the reduction with “Bu6CrLi3” react with oxiranes to afford γ-hydroxy esters and β-hydroxy esters, depending on the Lewis acid used as a promoter.
The first catalytic approach to the nucleophilic addition of silyl ketene acetals 2 to epoxides 1 is reported. The defined protocol is metal-free using tetrabutylammonioum fluoride as the catalyst. It works in a very efficient manner under solvent-free conditions (SolFC) allowing ?-lactones 3 to be directly obtained with high regioselectivities and yields.