title: Pd-PEPPSI-IPent: an active, sterically demanding cross-coupling catalyst and its application in the synthesis of tetra-ortho-substituted biaryls.
abstract: Incredible Bulk: A series of N-heterocyclic carbene catalysts (see picture) were prepared and evaluated in the Suzuki-Miyaura reaction. A variety of sterically encumbered tetra-ortho-substituted biaryl products were formed from unreactive aryl chlorides using the isopentyl-substituted catalyst at temperatures ranging from 65 degrees C to room temperature. The cyclopentyl-substituted catalyst was virtually inactive, demonstrating that "flexible bulk" is essential to promote these transformations.
authors.affiliation: Department of Chemistry, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Organ
authors.forename: Selçuk
authors.initials: S
authors.lastname: Calimsiz
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Sayah
authors.forename: Ka Hou
authors.initials: KH
authors.lastname: Hoi
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Lough