Benzodioxole Chemistry.5.Dramatic substituent effect in the reaction of carbonyl-Bridged cyclic carbonates with methoxide ion

摘要

Benzodioxolediones(2c-e)undergo high-yield conversion to cyclopentenones(3c-e_ in K_2CO_3/MeOH at room temperature,while analogs(2a) and (2b) yield exclusively cyclohexadiene carboxylates (1a and 1b) under these conditions.isolation of intermediate 6(R,R'-Me R"=Ph) from the reaction of 2c with K_2CO_3/MeOH at 5-10 degC suggests that 3 is formed in a process triggered by attack of OMe~(-) at the ester carbonyl of 2.