Manganese(III) acetate mediated oxidative free radical reactions between indole derivatives and 1,3-dicarbonyl compounds

Manganese(III) mediated oxidative free radical reactions between indole derivatives and 1,3-dicarbonyl compounds are described. In the presence of dimethyl malonate, the oxidative free radical reaction of 3-unsubstituted indoles resulted in the formation of 2-(3-oxo-2-indolylidene)malonates and these malonates can be prepared in much better yields from corresponding 3-indolecarboxylic acids. On the contrary, the oxidative free radical reaction between 3-unsubstituted indoles and 2,4-pentanedione or ethyl acetoacetate gave furo[3,2-b]indoles.{A figure is presented}.