Facile conversion of amides and lactams to selenoamides and selenolactams using tetraethylammonium tetraselenotungstate

Chloroiminium salts generated in situ from amides and lactams using (COCl)2 or POCl3 react very readily with the new selenium transfer reagent, tetraethylammonium tetraselenotungstate, (Et4N)2WSe4, 1, to afford the corresponding selenoamides and selenolactams in excellent yields under mild reaction conditions.