An efficient synthesis of achiral and chiral 1,2,4-triazolium salts: bench stable precursors for N-heterocyclic carbenes.
[reaction: see text] The promising utility of triazolyl N-heterocyclic carbene catalysts in umpolung aldehyde chemistry requires a straightforward reliable synthesis from readily available materials. Herein, we describe the synthesis of a variety of triazolyl N-heterocyclic carbene precursors. The reactions commence from commercially available amino acids and proceed in 44-68% overall yields. The N-heterocyclic salts are air-stable crystalline solids that can be stored with no special precaution and can generate the active catalyst when treated with an appropriate base.
Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA.
Mark S
MS
Kerr
Javier
J
Read de Alaniz
Tomislav
T
Rovis
D002384:Catalysis; D006571:Heterocyclic Compounds / Q000138:chemical synthesis; D006838:Hydrocarbons; D008697:Methane / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D008956:Models, Chemical; D012492:Salts / Q000737:chemistry*; D013237:Stereoisomerism; D014230:Triazoles / Q000138:chemical synthesis*
D006571:Heterocyclic Compounds; D006838:Hydrocarbons; D012492:Salts; D014230:Triazoles; C030011:carbene; C045575:1,2,4-triazole; D008697:Methane