Synthesis of 2,3-dihydroselenazolo[3,2-a]pyridinium salts based on reactions of pyridine-2-selanyl chloride with alkenes and dienes

The reaction of pyridine-2-selanyl chloride with alkenes and dienes gives 2,3-dihydro[1,3]selenazolo[3,2-a]pyridinium derivatives as addition-cyclization products involving closure of the ring at the pyridine nitrogen atom of the selanylating electrophile.