Different metal salts catalyzed alkylation or cycloaddition of indolylquinones with diethyl malonate via base-mediated

• We report a simple and efficient alkylation of indolylquinones, using diethyl malonate as alkylating reagents and the cycloaddition of indolylquinones with diethyl malonate. These reaction proceeds under mild conditions with a broad substrate scope and wide functional group tolerance to provide the alkylated indolylquinones and polycyclic quinones N-heterocycles in good yields. • The scope of the substrates is broad to give 42 novel compounds in good yields. • Structure of all the products was ascertained by NMR, HRMS analysis and further confirmed by single crystal X-ray diffraction of four of the product ( 3a and 4l ). • The developed protocol is amenable for a scale-up reaction and which has shown through gram scale reaction for the synthesis of 3a and 4a . • The mechanism of the reaction has been proposed based on a series of control experiments. Different metal salts catalyzed alkylation or cycloaddition of indolylquinones with diethyl malonate via base-mediated have been developed. Due to differences in alkalinity and metal coordination, copper catalysis and zinc catalysis exclusively afforded selective products. This reaction offers an approach to generating the alkylated indolylquinones and polycyclic quinones N-heterocycles in 57- 89 % yields. We report a simple and efficient base-mediated direct alkylation of indolylquinones, using diethyl malonate as alkylating reagents and the direct [4 + 1] cycloaddition of indolylquinones with diethyl malonate. These reaction proceeds under mild conditions with a broad substrate scope and wide functional group tolerance to provide the alkylated indolylquinones and polycyclic quinones N-heterocycles in good yields.