Thia-Prins Bicyclization Approach for the Stereoselective Synthesis of Dithia- and Azathia-Bicycles
datasetposted on 21.06.2013, 00:00 by B. V. Subba Reddy, A. Venkateswarlu, Prashant Borkar, J. S. Yadav, M. Kanakaraju, A. C. Kunwar, B. Sridhar
A novel thia-Prins bicyclization approach has been developed for the first time for the synthesis of hexahydro-2H-thieno[3,2-c]thiopyran derivatives from the coupling of homoallylic mercaptans such as hex-3-ene-1,6-dithiol with various aldehydes using 10 mol % InBr3 in dichloromethane with high selectivity. In addition, the coupling of (E)-N-(6-mercaptohex-3-enyl)-4-methylbenzenesulfonamide with aldedydes affords the corresponding N-tosyloctahydrothiopyrano[4,3-b]pyrrole derivatives in good yields. This reaction is a stereoselective affording trans-fused product from E-homoallyllic mercaptan and cis-fused product from Z-homoallyllic mercaptan.