Synthesis of Fused and Linked Benzofurans from 2-Alkynylphenol Derivatives through Rhodium(I)-catalyzed Domino-type Addition Reactions.

A rhodium(I)-catalyzed domino-type sequential 5-/5- cyclization reaction of [(2-acylphenyl) ethynyl]phenols produces indene/benzofuran-fused alcohols. A moderate asymmetric induction is observed when chiral diphosphine ligands are used for rhodium. Indene/indole-fused compounds are synthesized by a similar reaction of [(2-acetylphenyl)ethynyl]anilines.