Cycloadditions of 3,4-Dihydro-2<i>H</i>-pyrrole <i>N</i>-Oxide with Thioketones and a Selenoketone

Abstract

Abstract Cycloadditions of 2-diphenylphosphinoyl-2-methyl-3,4-dihydro-2H-pyrrole N-oxide (DPhPMPO), 3,4-dihydro-2H-pyrrole N-oxide having a diphenylphosphinoyl group at the C2 position with thioketones afforded the corresponding 1,4,2-oxathiazolidines. Dissociation constants of these 5-membered ring products were determined. The cycloadducts were stabilized by the diphenylphosphinoyl group. The reaction of DPhPMPO with di-tert-butyl selenoketone gave the corresponding selenoamide under microwave irradiation. The formation of the selenoamide indicated that the cycloaddition of DPhPMPO with the selenoketone analogue also proceeded through the formation of the corresponding 5-membered ring product.