501365-08-8Relevant articles and documents
Stereoselective synthesis of homochiral substituted tetrahydrothiophenes by electrophile-promoted thioetherification
Jana, Gourhari,Viso, Antonio,Diaz, Yolanda,Castillon, Sergio
, p. 209 - 216 (2007/10/03)
In this paper we study the electrophile-promoted cyclization of 2-sulfanyl-4-penten-1-ol and 1-sulfanyl-4-penten-2-ol derivatives as a way of preparing cyclic sulfides. The reaction is completely chemoselective and always proceeds by activation of the sulfur centre. The reaction of 2-sulfanyl-4-penten-1-ol derivatives proceeds by a 5-endo mode. Unsaturated thiol 6 undergoes iodine-promoted cyclothioetherification to give the tetrahydrothiophene 9 in moderate yields and with excellent regio- and stereoselectivity. However, when the reaction starts from the benzyl sulfide 7, a diastereomeric mixture of 9 and 10 is obtained in good yields. Selenium-promoted cyclization of unsaturated thioacetate 5 provides the selenyltetrahydrothiophene 12 or the sulfanyl acetate 13, depending on the selenium reagent used. On the other hand, electrophile-induced cyclization of 1-sulfanyl-4-penten-2-ol derivatives 23-25 depends on the electrophile used. Iodothioetherification of benzyl sulfide 25 followed by oxidation affords unsaturated sulfone 26 as a result of 6-endo-cyclization, dehydroiodination and oxidation. In contrast, selenothiocyclization of 24 with PhSeX results in the formation of the 5-exo tetrahydrothiophenes 29/30 and/or 31/32. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
