STABLE SELENOXANTHENIUM YLIDES : SYNTHESIS AND NEW REDUCTIVE CYCLIZATION OF SELENOXANTHEN-10-IO(ALKOXALYL ALKOXYCARBONYL)METHANIDES AND THEIR RELATED COMPOUNDS

Article abstract of DOI:10.1016/S0040-4039(00)81331-3

Stereoisomers of 9-substituted selenoxanthen-10-io(alkoxalyl alkoxycarbonyl)methanides were prepared from the corresponding selenoxides and activated acetylenes.In the reaction of 9-phenylselenoxanthene 10-oxide(1c) with methyl propiolate afforded an unexpected product, methyl 9-phenylselenoxanthen-9-ylpropiolate(5) together with ylide(2e).The selenonium ylides underwent new reductive cyclization with sodium borohydride to afford new cyclic selenonium ylides.