US EPA

8203497 

Journal Article 

4-Fluoropyrrolidine-2-carbonyl fluorides: useful synthons and their facile preparation with 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride 

Singh, RP; Umemoto, T; , 

2011 

Yes 

Journal of Organic Chemistry
ISSN: 0022-3263
EISSN: 1520-6904 

AMER CHEMICAL SOC 

WASHINGTON 

76 

9 

3113-3121 

English 

21446739 

10.1021/jo1025783 

WOS:000289956900016 

https://pubs.acs.org/doi/10.1021/jo1025783
Exit
 

4-Fluoropyrrolidine derivatives are useful in medicinal chemistry applications such as dipeptidyl peptidase IV inhibitors. As attractive synthons for these, N-protected (2S,4S)-4-fluoropyrrolidine-2-carbonyl fluorides were synthesized in high yield by double fluorination of N-protected (2S,4R)-4-hydroxyproline with 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride (Fluolead). The 4-fluoropyrrolidine-2-carbonyl fluorides were converted to useful intermediates such as 4-fluoropyrrolidine-2-carboxamides, -N-methoxy-N-methylcarboxamide (Weinreb amide), -carboxylate methyl esters, and -carbonitriles in excellent yields. The crystalline N-Fmoc-cis-4-fluoropyrrolidine-2-carbonyl fluoride 2a is a particularly useful synthon due to its high yield of preparation and easy isolation as an enantiomerically pure compound by crystallization. Thus, the methodology using the synthons prepared by the stereospecific double fluorination has enabled a significant decrease in the synthetic steps needed for the preparation of the 4-fluoropyrrolidine derivatives useful for medicinal applications.