A diversity-oriented synthesis of caroverine derivatives via TEMPO-promoted aerobic oxidative CN bond formation

A concise method has been developed for the synthesis of caroverine and its derivatives. The quinoxalinone scaffold of these compounds was constructed via the tandem nitrosation/aerobic oxidative CN bond formation reaction of N-(2-chloroethyl)-2-cyano-N-phenylacetamide, followed by sequential Grignard, Finkelstein and nucleophilic substitutions reactions to give several different derivatives. Herein, we describe the development of this strategy in terms of the optimization of each step as well as the effect of different additives on the individual reactions.