title: ZnBr2-Mediated Cascade Reaction of o-Alkoxy Alkynols: Synthesis of Indeno[1,2-c]chromenes.
abstract: A Lewis acid-mediated cascade annulation of o-alkoxy alkynols in the presence of ZnBr2has been developed. The cascade cyclization proceeds through a 5-exo-dig cyclization followed by a Friedel-Crafts reaction and ring-opening sequence to synthesize indeno[1,2-c]chromenes. This protocol provides a broad substrate scope in moderate to good yields with high regioselectivity. The reaction with benzo-fused cycloalkyl ketones gave an unexpected alkyne C-C bond cleavage resulting in fused polycycles.
authors.affiliation: Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , No. 100 Shiquan First Road, Sanmin District, Kaohsiung City 807, Taiwan.
authors.forename: Amol Milind
authors.initials: AM
authors.lastname: Garkhedkar
authors.affiliation: Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , No. 100 Shiquan First Road, Sanmin District, Kaohsiung City 807, Taiwan.
authors.forename: Gopal Chandru
authors.identifier: 0000-0003-0149-5423
authors.initials: GC
authors.lastname: Senadi
authors.affiliation: Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , No. 100 Shiquan First Road, Sanmin District, Kaohsiung City 807, Taiwan.|Department of Medical Research, Kaohsiung Medical University Hospital , No. 100 Tzyou First Road, Sanmin District, Kaohsiung City 807, Taiwan.
authors.forename: Jeh-Jeng
authors.identifier: 0000-0002-3148-1885
authors.initials: JJ
authors.lastname: Wang