Synthesis 1998; 1998(2): 195-200
DOI: 10.1055/s-1998-2012
paper
© 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.

Synthesis of PO(OR)2- and PR3 +-Disubstituted Pyridines via N-(Trifluoromethylsulfonyl)pyridinium Triflates

Mirko Haase* , Helmar Goerls, Ernst Anders
  • *Institut für Organische Chemie und Makromolekulare Chemie der Universität Jena, Humboldtstraße 10, D-07743 Jena, Germany; Fax + 49(36 41)94 82 12; E-mail: c5eran@rz.uni-jena.de
Further Information

Publication History

Publication Date:
31 December 2000 (online)

The efficient synthesis of dialkoxyphosphoryl- and phosphonio-substituted pyridines is reported. The cationic heterocycle of N-(trifluoromethylsulfonyl)pyridinium triflate (3), or of analogous N-(trifluoromethylsulfonyl) compounds prepared from pyridine-4-phosphonium salts 5, turns out to be sufficiently activated to allow attack of P(OR)3 and PR3 nucleophiles to give the novel compounds bis(dialkoxyphosphoryl)pyridines 11 and phosphonio(dialkoxyphosphoryl)pyridines 13. For example, 13 a - d, with PO(OR)2 at the C2 and PR3 + at the C4 position, represent the first examples of an N-heteroaromatic ring substituted by both dialkoxyphosphoryl and phosphonio moieties. The structure of 13 b [PPh3 +/PO(O-i-Pr)2] was confirmed by X-ray analysis. In most cases, the intermediate 1-(trifluoromethylsulfonyl)dihydropyridines, such as 7, 8 (monosubstituted) or 10 a and b and 12 a - d (disubstituted), are sufficiently stable for isolation.