Homolytic substitution by iminyl radical at selenium: A free-radical route to 1,2-benzoselenazoles

Article abstract of DOI:10.1016/S0040-4039(00)79347-6

Thiohydroxamic esters (3) derived from the O-carboxymethyl oxime derivatives (2) of 2-(benzylseleno)-benzaldehyde (1: R = H), 2-(benzylseleno)acetophenone (1: R = Me) and 2-(benzylseleno)propiophenone (1: R = Et) decompose smoothly, upon irradiation, with the loss of carbon dioxide and formaldehyde to give the 1,2-benzoselenazoles (5). The reaction presumably involves the iminyl radical intermediate (4) which undergoes intramolecular free-radical homolytic substitution at selenium to afford the product (5).