How is 1,3,2-Dioxathiane 2,2-dioxide (CAS: 1073-05-8) typically synthesized?

1,3,2-Dioxathiane 2,2-dioxide is typically synthesized through the condensation of methyl acetylenedicarboxylate with dimethyl sulfide in the presence of a strong base like potassium tert-butoxide. The reaction yield is usually high (around 90%), and the product is purified by recrystallization from ethanol. The use of appropriate catalysts and optimal reaction conditions ensures high selectivity and yield.