Fluorine-Directed Nazarov Cyclizations 2: Regioselective Synthesis of 5-Trifluoromethyl-2-cyclopentenones

Junji Ichikawa; Masaki Fujiwara; Tatsuo Okauchi; Toru Minami

doi:10.1055/s-1998-1817

Synlett 1998; 1998(8): 927-929
DOI: 10.1055/s-1998-1817

letter

© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

Fluorine-Directed Nazarov Cyclizations 2: Regioselective Synthesis of 5-Trifluoromethyl-2-cyclopentenones

Junji Ichikawa^* , Masaki Fujiwara, Tatsuo Okauchi, Toru Minami

^*Department of Applied Chemistry, Kyushu Institute of Technology, Sensui-cho, Tobata, Kitakyushu 804-8550, Japan; Fax 81 93 884 3314; E-mail: ichikawa@che.kyutech.ac.jp

Abstract

PDF Download All articles of this category

1-Trifluoromethylvinyl vinyl ketones are treated with trimethylsilyl trifluoromethanesulfonate in CH₂Cl₂-1,1,1,3,3,3-hexafluoro-2-propanol to afford 5-trifluoromethyl-2-cyclopentenones. Both acyclic and cyclic substrates furnish the corresponding cyclized products in good to excellent yields with defined placement of the endocyclic double bond due to the strong electronic effect exerted by the trifluoromethyl group.

fluorinated divinylketone - Nazarov cyclization - Lewis acid - carbocation - trifluoromethylated cyclopentenone

PDF (42 kb)