Synthesis of 1,4-dithiins and 1,4-diselenins from alkynes and elemental sulfur/selenium under transition metal-free conditions with high regioselectivity

A straightforward protocol for the synthesis of various 1,4-dithiines and 1,4-diselenins starting from alkynes and elemental sulfur/selenium with high regioselectivity under transition metal-free conditions is demonstrated.