The influence of substituents on the kinetics of the reaction of carbonyl oxides with benzaldehyde

The reactivity of carbonyl oxides toward benzaldehyde was characterized by thek33/k33 ratio, wherek33 andk31 are the rate constants of the reactions of RCOO with PhCHO and diphenyldiazomethane Ph2CN2, respectively. Thek33/k31 ratios obtained at 60°C in acetonitrile range from 0.61·10−2 (m-BrPh2CN2) to 20·10−2 (Ph2MeCHO). The reactions are probably preceded by the formation of a charge-transfer complex (CTC) with charge transfer from aldehyde to RCOO. The carbonyl oxide reacts with aldehydes by both the nucleophilic pathway (at the C atom of the—CHO group to form 1,2,4-trioxolane) and electrophilic pathway (by the attack at the aromatic ring with the intermediate formation of CTC). In the latter case, either 1,2,4-trioxolane or oxidation products of the phenyl ring are formed.