An unusual Me_3SiI-promoted 4+2 annulation and reduction: An efficient approach to construct 4H-benzopyrans

摘要

Me_3SiI-promoted reaction of salicylic aldehydes with β-dicarbonyl compounds provided a facile way to construct 4H-benzopyrans in moderate to good yields. This tandem reaction proceeds with high efficiency through nucleophilic addition, silyl enol ether formation, substitution, reduction, and intramolecular nucleophilic cyclization.