1. Department of Chemistry, York University, 4700 Keele Street, Toronto, ON, M3J 1P3 (Canada), Fax: (+1)?416‐736‐5936;2. Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6 (Canada)
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 °C to room temperature. The cyclopentyl‐substituted catalyst was virtually inactive, demonstrating that “flexible bulk” is essential to promote these transformations.
