title: Cyclization of 4-Phenoxy-2-coumarins and 2-Pyrones via a Double C-H Activation.
abstract: Aryl-heteroaryl coupling via double C-H activation is a powerful transformation that avoids the installation of activating groups. A double C-H activation of privileged biological scaffolds, 2-coumarins and 2-pyrones, is reported. Despite the rich chemistry of these molecular frameworks, the yields are very good. Excellent regioselectivity was achieved on the pyrones. This methodology was applied to the synthesis of flemichapparin C in three steps. Isotope effect experiments were carried out, and a mechanism is proposed.
authors.affiliation: Department of Chemistry and Analytical & Biological Chemistry Research Facility, University College Cork , College Road, Cork, Ireland.
authors.forename: Katrina
authors.initials: K
authors.lastname: Mackey
authors.affiliation: Department of Chemistry and Analytical & Biological Chemistry Research Facility, University College Cork , College Road, Cork, Ireland.
authors.forename: Leticia M
authors.initials: LM
authors.lastname: Pardo
authors.affiliation: Department of Chemistry and Analytical & Biological Chemistry Research Facility, University College Cork , College Road, Cork, Ireland.
authors.forename: Aisling M
authors.initials: AM
authors.lastname: Prendergast
authors.affiliation: Department of Chemistry and Analytical & Biological Chemistry Research Facility, University College Cork , College Road, Cork, Ireland.
authors.forename: Marie-T
authors.initials: MT
authors.lastname: Nolan
authors.affiliation: Department of Chemistry and Analytical & Biological Chemistry Research Facility, University College Cork , College Road, Cork, Ireland.
authors.forename: Lorraine M
authors.initials: LM
authors.lastname: Bateman
authors.affiliation: Department of Chemistry and Analytical & Biological Chemistry Research Facility, University College Cork , College Road, Cork, Ireland.
authors.forename: Gerard P
authors.initials: GP
authors.lastname: McGlacken