Titanium-catalyzed stereoselective geminal heterodihalogenation of beta-ketoesters

Richard Frantz; Lukas Hintermann; Mauro Perseghini; Diego Broggini; Antonio Togni

doi:10.1021/ol0343459

Titanium-catalyzed stereoselective geminal heterodihalogenation of beta-ketoesters

Org Lett. 2003 May 15;5(10):1709-12. doi: 10.1021/ol0343459.

Authors

Richard Frantz¹, Lukas Hintermann, Mauro Perseghini, Diego Broggini, Antonio Togni

Affiliation

¹ Department of Chemistry, Swiss Federal Institute of Technology, ETH Hönggerberg, CH-8093 Zürich, Switzerland.

PMID: 12735758
DOI: 10.1021/ol0343459

Abstract

[reaction: see text] beta-Ketoesters can be effectively monofluorinated with F-TEDA using CpTiCl(3) as a catalyst. With the use of this catalyst, the extent of the competing difluorination does not reach 10%. [TiCl(2)(TADDOLato)] complexes catalyze the one-pot enantioselective heterodihalogenation of beta-ketoesters with F-TEDA and NCS to afford alpha-chloro-alpha-fluoro-beta-ketoesters in moderate to good yields. The sequence of addition of the halogenating agents determines the sense of chiral induction.