Bismuth triflate-catalyzed oxa- and thia-Pictet-Spengler reactions:: access to iso- and isothio-chroman compounds

A new route to functionalized iso(thio)chromans is described. The compounds are accessible easily in a one pot-reaction by using different benzaldehydes and phenylethanethiol or phenylethanol in presence of bismuth triflate. (C) 2008 Elsevier Ltd. All rights reserved.