Employed in the synthesis of enones by selenenylation of α-cyano ketones with lithium naphthalenide. Phenylselenyl bromide was used in the preparation of exo-2-methyl-7-phenylselenyl-octahydro-8-oxa-2,7b-diaza-dicyclopenta[a,e]pentalene-1,3-dione and endo-2-methyl-7-phenylselanyl-octahydro-8-oxa-2,7b-diaza-dicyclopenta[a,e]pentalene-1,3-dione.