N-heterocyclic carbene catalyzed enantioselective α-fluorination of aliphatic aldehydes and α-chloro aldehydes: synthesis of α-fluoro esters, amides, and thioesters.
The asymmetric fluorination of azolium enolates that are generated from readily available simple aliphatic aldehydes or α-chloro aldehydes and N-heterocyclic carbenes (NHCs) is described. The process significantly expands the synthetic utility of NHC-catalyzed fluorination and provides facile access to a wide range of α-fluoro esters, amides, and thioesters with excellent enantioselectivity. Pyrazole was identified as an excellent acyl transfer reagent for catalytic amide formation.
Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR (China); Department of Chemistry, Jinan University, Guangzhou 510632 (China).
Xiuqin
X
Dong
Wen
W
Yang
Weimin
W
Hu
Jianwei
J
Sun
D000447:Aldehydes / Q000737:chemistry*; D004952:Esters / Q000138:chemical synthesis; D005461:Fluorine / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D013237:Stereoisomerism
D000447:Aldehydes; D004952:Esters; D006571:Heterocyclic Compounds; C030011:carbene; D005461:Fluorine; D008697:Methane
N-heterocyclic carbenes; asymmetric catalysis; enolates; fluorine; organocatalysis