Heterocyclization of ketoximes with propyne or allene in superbase systems MOR/DMSO (M = K, Cs; R = H, t-Bu), which leads to 2-alkyl(aryl, hetaryl)-5-methyl-and 2,3-dialkyl-5-methylpyrroles or 2-methyl-4,5,6,7-tetrahydroindole in yields of up to 63%, has been accomplished for the first time. The reaction is mostly regioselective affording mainly or exclusively 2,5-di-and 2,3,5-trisubstituted pyrroles. The minor isomers in most cases are the corresponding 2,4-di-and 2,3,4-trisubstituted pyrroles, only in the case of acetoxime the isomer ratio is ca 1:1. For oximes of methyl isopropyl ketone and pinacolone, the 4-methyl-isomers become predominant (78, 83%, respectively).
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.