Cyano-substituted 5-thiabicyclo[2.1.0]pent-2-enes: reactions and relevance to cyanothiophen phototranspositions

Abstract

Cyano-substituted 5-thiabicyclo[2.1.0]pent-2-enes have been detected and shown to be intermediates in the phototransposition of cyanothiophens; one such ‘Dewar thiophen’, 2-cyano-3-methyl-5-thiabicyclo[2.1.0]pent-2-ene, has been isolated and fully characterised, and its aromatisation and rearrangement by sulphur walk, both of which occur photochemically as well as thermally, and its Diels–Alder reactions with furan and 2,5-diphenyl-3,4-benzofuran have been studied.