title: OH-directed alkynylation of 2-vinylphenols with ethynyl benziodoxolones: a fast access to terminal 1,3-enynes.
abstract: The first direct alkynylation of 2-vinylphenols was developed. The rationally optimized hypervalent iodine reagent TIPS-EBX* in combination with [(Cp*RhCl2)2] as a C-H-activating transition metal catalyst enables the construction of a variety of highly substituted 1,3-enynes in high yields of up to 98%. This novel C-H activation method shows excellent chemoselectivity and exclusive (Z)-stereoselectivity, and it is also remarkably mild and tolerates a variety of functional groups. Furthermore, synthetic modifications of the resulting 1,3-enynes were demonstrated. To our knowledge, this is the first example for an OH-directed C-H alkynylation with hypervalent iodine reagents.
authors.affiliation: Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18 (Germany).
authors.forename: Peter
authors.initials: P
authors.lastname: Finkbeiner
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kloeckner
authors.forename: Boris J
authors.initials: BJ
authors.lastname: Nachtsheim
keywords: CH activation; alkynes; enynes; iodine; rhodium