Synfacts 2009(6): 0673-0673  
DOI: 10.1055/s-0029-1216770
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart ˙ New York

A Fluorinated ”Designer" Organocatalyst

Contributor(s): Benjamin List, Olga Lifchits
C. Sparr, W. B. Schweizer, H. M. Senn, R. Gilmour*
ETH Zürich, Switzerland and University of Glasgow, Scotland, UK
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Publikationsverlauf

Publikationsdatum:
25. Mai 2009 (online)

Significance

Gilmour and colleagues report the study and application of commercially available 2-(fluorodiphenylmethyl)pyrrolidine 2 as a secondary amine organocatalyst. The authors hypothesized that a fluorine atom beta to the pyrrolidine nitrogen would lead to a pronounced preference for a gauche conformation of the iminium intermediate of type 1, possibly resulting in enhanced asymmetric induction. Crystallographic and computational studies were used to support this hypothesis. As proof of principle, catalyst (S)-2 was applied to a Weitz-Scheffer epoxidation. The observed enantioselectivity of catalyst (S)-2 proved to be comparable to the original Jørgensen catalyst 4 (J. Am. Chem. Soc. 2005, 127, 6964) and superior to the non-fluorinated analogue 3.