title: BCl3-Induced Annulative Oxo- and Thioboration for the Formation of C3-Borylated Benzofurans and Benzothiophenes.
abstract: BCl3-induced borylative cyclization of aryl-alkynes possessing ortho-EMe (E=S, O) groups represents a simple, metal-free method for the formation of C3-borylated benzothiophenes and benzofurans. The dichloro(heteroaryl)borane primary products can be protected to form synthetically ubiquitous pinacol boronate esters or used in situ in Suzuki-Miyaura cross couplings to generate 2,3-disubstituted heteroarenes from simple alkyne precursors in one pot. In a number of cases alkyne trans-haloboration occurs alongside, or instead of, borylative cyclization and the factors controlling the reaction outcome are determined.
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Warner
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Churn
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
authors.forename: John S
authors.initials: JS
authors.lastname: McGough
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
authors.forename: Michael J
authors.identifier: 0000-0001-9975-8302
authors.initials: MJ
authors.lastname: Ingleson
keywords: annulation; borylation; cross coupling; electrophilic cyclization; organoboranes