Kinetics and Mechanism of Isocyanide-Promoted Carbene Insertion into the Aryl Substituent of an N-Heterocyclic Carbene Ligand in Ruthenium-Based Metathesis Catalysts
作者:Justin R. Griffiths、Elan J. Hofman、Jerome B. Keister、Steven T. Diver
DOI:10.1021/acs.organomet.7b00342
日期:2017.8.28
In situ IR spectroscopy was used to study the kinetics of addition of L = alkyl and aryl isocyanides to the Grubbs second-generation carbene complex Ru(H2IMes)(CHPh)(PCy3)Cl2 (H2IMes = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene), which triggers carbene insertion into an aromatic ring of the N-heterocyclic carbene supporting ligand, forming Ru1-mesityl-3-(7′-Ph-2′,4′,6′-trimethylcycloheptatrienyl)-4
使用原位红外光谱研究了将L =烷基和芳基异氰酸酯添加到Grubbs第二代卡宾络合物Ru(H 2 IMes)(CHPh)(PCy 3)Cl 2(H 2 IMes = 1,3 -dimesityl-4,5-dihydroimidazol-2-ylidene),触发卡宾插入N杂环卡宾支持配体的芳香环,形成Ru 1-mesityl-3-(7'-Ph-2',4 ′,6′-三甲基环庚三烯基)-4,5-二氢咪唑-2-亚基} L 2(PCy 3)Cl 2。速率定律被确定为异氰化物浓度为一阶,卡宾络合物浓度为一阶。对于各种异氰化物,CNR的比率随着R =叔数的增加而增加丁基≪环己基<正辛基