Umpolung of Michael acceptors catalyzed by N-heterocyclic carbenes.
N-Heterocyclic carbenes can catalyze beta-alkylations of a range of alpha,beta-unsaturated esters, amides, and nitriles that bear pendant leaving groups to form a variety of ring sizes. In this process, the nucleophilic catalyst transiently transforms the normally electrophilic beta carbon into a nucleophilic site through an unanticipated addition-tautomerization sequence.
Fischer
Christian
C
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Smith
Sean W
SW
Powell
David A
DA
Fu
Gregory C
GC
D000475:Alkenes / Q000737:chemistry*; D000478:Alkylation; D002384:Catalysis; D003500:Cyclization; D006571:Heterocyclic Compounds / Q000737:chemistry*; D006838:Hydrocarbons / Q000737:chemistry; D006844:Hydrocarbons, Cyclic / Q000138:chemical synthesis*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry
D000475:Alkenes; D006571:Heterocyclic Compounds; D006838:Hydrocarbons; D006844:Hydrocarbons, Cyclic; C030011:carbene; D008697:Methane