Divergent and facile Lewis acid-mediated synthesis of N-alkyl 2-aminomethylene-1,3-indanediones and 2-alkylamino-1,4-naphthoquinones

N-Alkyl 2-aminomethylene-1,3-indanediones and 2-alkylamino-1,4-naphthoquinones are known for their diverse and versatile bioactivities and applications. Traditionally, these two compounds were synthesized in separate routes using different materials. By employing Lewis acid, cycloaddition of alkyl azides and 1,4-naphthoquinone can provide these two classes of compound in one-pot fashion. Among the Lewis acids and conditions examined, TMSOTf under reflux offers the best overall yields. In addition, the purification of both classes of compounds can be easily achieved using flash column chromatography making this methodology feasible for scale-up synthesis of compounds with biological interests.