Polycyclic molecules and tetrahydroquinoleines were obtained in a tandem reaction involving the diastereoselective addition of alpha-aminoalkyl radicals to (5R)-5-menthyloxy-2[5H]-furanone 1. The facial diastereoselectivity on 1 is >/=90%. The alpha-aminoalkyl radicals were produced from tertiary amines by photochemical-induced electron transfer. When N,N-dialkylanilines 19 were used as starting tertiary amines, a rearomatization step was involved and important side reactions of 1 were observed. A mechanistic study involving isotopic labeling of the starting amine indicated that the byproducts resulted from reduction of 1 during the rearomatization process. An efficient optimization of the reaction was obtained by simply adding acetone or cyclopentanone as mild oxidants to the reaction mixture. The side products resulting from reduction of the furanone 1 were completely suppressed under these conditions, and the yields of the tetrahydroquinolines 21a-i, 22a-f, and 26g-i were doubled.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.