Investigations into the mechanism of regioselective C-deuteriation of enolates under ‘base-free’ conditions

Regioselective C-deuteriation of enolates was efficiently achieved by quenching the corresponding base-free enolate in the presence of a carbonyl chelating deuterium source. We comment on factors (such as the presence of base and the structural nature of the deuterium reagent) that are responsible for this observed regioselectivity and comment on the role of the deuterium source.