Organ Michael G, Calimsiz Selçuk, Sayah Mahmoud, Hoi Ka Hou, Lough Alan J
Department of Chemistry, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada.
Angew Chem Int Ed Engl. 2009;48(13):2383-7. doi: 10.1002/anie.200805661.
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.
制备了一系列氮杂环卡宾催化剂（见图），并在铃木-宫浦反应中对其进行了评估。使用异戊基取代的催化剂，在65℃至室温的温度范围内，由无反应活性的芳基氯生成了多种空间位阻较大的四邻位取代联芳基产物。环戊基取代的催化剂几乎没有活性，这表明“柔性体积效应”对于促进这些转化至关重要。
