The dichlorobis (tripheny1phosphine) palladium (PdCl2 (PPh&-tin (II) chloride (SnC12) system shows high catalytic activity for the reductive N-heterocyclization of various 2- nitrostyrene and N-(2-nitrobenzy1idene) amine derivatives when employed at 100" C for 16 h under 20 kg cm-2 of initial carbon monoxide pressure, to give the corresponding indole and W-indazole derivatives in good yield. For example, 2-phenylindole was obtained in ...