Iron(II)-catalyzed direct C–H cyanoalkylation of 2H-indazoles and coumarins via radical C–C bond cleavage

An iron-catalyzed C-3 cyanoalkylation of 2H-indazole and coumarin derivates with cyclobutanone oxime esters has been accomplished, which proceeds efficiently in a high regioselective manner to construct diverse alkylated 2H-indazole and coumarin derivates in moderate to good yields. Preliminary mechanistic studies reveal that a distal cyanosubstituted alkyl radicals intermediate would be formed through radical-involved C–C bond cleavage of cyclobutanone oximes ester.