The question of electrophilic vs nucleophilic addition of cyclic β-dicarbonyl phenyliodonium ylides: Electrophilic cycloaddition of diphenylketene

Article abstract of DOI:10.1021/jo3020787

The reaction of β-dicarbonyl phenyliodonium ylides with diphenylketene at room temperature affords mixtures of lactone and aurone derivatives. The initial electrophilic attack of the iodonium ylide on the C_β position of the diphenylketene, followed by cyclization of the zwitterionic species, and subsequent ejection of iodobenzene, affords the lactone and aurone cycloadducts. Treatment of β-dicarbonyl iodonium ylides with acyl chlorides yields α-chloroenones with good to excellent yields.