Electron impact studies. Part 143. An ion cyclotron resonance study of the gas-phase reactions of alkoxide ions with dialkyl carbonates

Abstract

The reaction between an alkoxide ion R¹O^– and a dialkyl carbonate (R²O)₂CO produces the product ions R¹OCO₂^– and R²OCO₂^–. The former ion is produced by nucleophilic attack of R¹O^– at the carbonyl centre of the dialkyl carbonate, whereas the latter ion is produced by attack of alkoxide ions at both the carbonyl centre and at an alkyl group R². The results obtained from ²H- and ¹⁸O-labelling studies suggest that the decomposing species formed during nucleophilic addition to the carbonyl centre has a tretrahedral structure. No stable species corresponding to [R¹O^–+(R²O)₂CO] is observed. The extent of nucleophilic attack at the carbonyl centre (compared with that at the alkyl group R²) decreases with elaboration of the alkyl groups R¹ or R².