Carbanion rearrangements. Collision-induced dissociations of tertiary carbanions derived from alkyl esters

Abstract

The collisional activation mass spectra of enolates R¹R²CO₂R³(R¹, R², and R³ are alkyl) show a variety of competitive fragmentations including the losses of H₂, R³˙, (R³O – H), and (R³O + H) together with the formation of R³O^– and R¹CCO^–. Deuterium labelling has been used to aid elucidation of mechanistic pathways. In one case, the elimination of R³OH from Et₂CO₂R³, the reaction involves prior hydrogen rearrangement before elimination of the alcohol.