Download PDF
Synthesis 1991; 1991(7): 575-580
DOI: 10.1055/s-1991-26520
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 2,3-Dihydro-1,4-dithiins and 2-Alkylidene-1,4-dithianes by 1,2-Sulfur Migration in 2-(1-Hydroxyalkyl)-1,3-dithiolanes

Carlos A. M. Afonso* , M. Teresa Barros, Licio S. Godinho, Christopher D. Maycock
  • *Department of Chemistry, New University of Lisbon, P-2825 Monte de Caparica, Portugal
Further Information

Publication History

Publication Date:
29 April 2002 (online)

  PDF Download  Permissions and Reprints All articles of this category

2,3-Dihydro-1,4-dithiins and the isomeric 2-alkylidene-1,4-dithianes were synthesized from 1,2-diketones and alkyl pyruvates by kinetically controlled ring expansion of 2-(1-hydroxyalkyl)-1,3-dithiolanes with p-toluenesulfonyl chloride in pyridine. In addition, 2,3-dihydro-1,4-dithiins, the thermodynamic products, were formed exclusively by using p-toluenesulfonic acid in refluxing benzene. The 2-alkylidene-1,4-dithianes were readily isomerised to the corresponding 2,3-dihydro-1,4-dithiins. Similarly, 2,3-dimethyl-6, 7-dihydro-5H-1,4-dithiepine and (+)-2-methylene-3-methyl-1,4-dithiepane were obtained from 2-[(S)-1-hydroxyethyl]-2-methyl-1,3-dithiane.