Unusual behaviour of 2,2-dimethyl-2H-chromene derivatives (precocenes) in phenylselenenylation

Abstract

Treatment of 2,2-dimethyl-2H-chromene derivatives (precocenes)(1) with benzeneselenenyl chloride in methylene dichloride solution affords a mixture of unusual phenylselenenylation products (7), (8), and (9) instead of the expected addition derivatives (3). In the case of 6-unsubstituted chromenes (1a,d,e), C-6 aromatic substitution (phenylselenenylation) takes place also.