In the reaction of the anion of Et diethylphosphonoacetate with p-nitrobenzylic derivatives either C-alkylation or O-alkylation may occur. Results showed that with decreasing ability of the leaving group from iodo, Br, Cl, OAc to N+(CH3)3I-, the SN2 O-alkylation or C-alkylation was inhibited, and the SRN 1 path, leading to C-alkylation, was facilitated. In the reaction of p-nitrobenzyl chloride with the anion, p,p'-dinitrostilbene was obtained. In the absence of electron transfer inhibitors or presence of only m-dinitrobenzene, the stilbene might be formed through SRN1 mechanism. In the presence of p-dinitrobenzene the mechanism might change to an SN2-elimination type.

Key words: ACETIC ACID ESTER, REACTION MECHANISM, ETHYL ACETATE, CHLOROHYDROCARBON, PHOSPHONIC ACID ESTER, BROMOHYDROCARBON, REARRANGEMENT REACTION, NITROBENZENE, BENZYL GROUP, ANION