The study on reactivity of several α-substituted α-sulfonyl malonates toward 1, 4- diazabicyclo [2.2. 2] octane (DABCO) and Bu3N is described. The reactivity with DABCO revealed the possible competition between decarbalkoxylation and unexpected desulfonylation, depending on the α-substituent, because of sterical hindrance around the electrophilic centers (SO2 and CO2R). The derivatives with crowded α-substituents suffer ...