1,3-Dipolar character of six-membered aromatic rings. Part 45. Photochemically-induced dimerisation of 1-vinyl- and 1-heteroaryl-3-oxidopyridiniums and related compounds

Abstract

Irradiations of 1-aryl-3-oxidopyridiniums and 2-methyl-4-oxidoisoquinolinium yield photochemically allowed symmetrical dimers, further chemical transformations of which are described. 1-H, 1-methyl, and 1-benzyl-3-oxidopyridiniums are photostable. 3-Oxido-1 -styrylpyridinium yields cycloadducts with a variety of 2π- and 4π-electron dipolarophiles as well as a photodimer.