Cyclic and acyclic sulfonimides in reactions with Rh(ii)-ketocarbenoids: a new access to chemoselective O-functionalization of the imidic carbonyl groups
diazomalonic, and diazoacetic esters using dirhodiumtetraacetate in the presence of isothiazol-3(2H)-one 1,1-dioxides and a number of N-(arenesulfonyl)carboxamides in solutions of methylene chloride or dichloroethane gives rise to O-alkylation of the imidic carbonyl groups by Rh(II)-carbenoids and the formation of O-alkylimidates as the final products. The reaction proceeds with high chemoselectivity via