The preparation of 3‐substituted 1,2‐benzisothiazole 1,1‐dioxides from lithiated intermediates or grignard reagents and methyl 2‐(aminosulfonyl)benzoate

A polylithiated β‐ketoester, β‐diketone, or β‐ketoamide was condensed‐cyclized with lithiated methyl 2‐(aminosulfonyl)benzoate, to afford new 3‐substituted 1,2‐benzisothiazole 1,1‐dioxides. Some Grignard or organolithium reagents were also condensed‐cyclized with methyl 2‐(aminosulfonyl)benzoate to give 3‐substituted 1,2‐benzisothiazole 1,1‐dioxides.