Synthesis of 3,4-disubstituted 2H-benzopyrans through C-C bond formation via electrophilic cyclization

[GRAPHIC] The electrophilic cyclization of substituted propargylic aryl ethers by I-2, ICl, and PhSeBr produces 3,4-disubstituted 2H-benzopyrans in excellent yields. This methodology results in vinylic halides or selenides under mild reaction conditions and tolerates a variety of functional groups, including methoxy, alcohol, aldehyde, and nitro groups.