An Atom-Economical approach to 2-Triazolyl Thio-/Seleno pyridines via Ruthenium-Catalyzed One-pot [3+2]/[2+2+2] cycloadditions

Abstract

An efficient method to access 2-triazolyl thio-/selenopyridines with good to excellent yields by ruthenium(II)-catalyzed one-pot [3+2]/[2+2+ 2] cycloaddition reactions of azides, 1-alkynyl thio-/ selenocyanates and 1,6-diynes is reported. This atom-economical catalytic strategy offers a mild and practical approach to access a variety of such cycloadducts with good to excellect regioselectivities. The protocol was further extended to the synthesis of 3,3’-bis(triazolyl thio-/seleno)-2,2’-bipyridines by the reaction of tetraynes with 1-alkynyl thio-/selenocyanates in the presence of aryl/alkyl azides.