Regarding the mechanism of olefin metathesis with sol-gel-supported ru-based complexes bearing a bidentate carbene ligand. Spectroscopic evidence for return of the propagating Ru carbene

被引:99
作者
Kingsbury, JS [1 ]
Hoveyda, AH [1 ]
机构
[1] Boston Coll, Merkert Chem Ctr, Dept Chem, Chestnut Hill, MA 02467 USA
关键词
D O I
10.1021/ja042668+
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Two isotopically and structurally labeled Ru-based carbenes (2-d(4) and 13) have been prepared and attached to the surface of monolithic sol-gel glass. The resulting glass-supported complexes (18-d(n) and 19) exhibit significant catalytic activity in promoting olefin metathesis reactions and provide products of high purity. Through analysis of the derivatized glass pellets used in a sequence of catalytic ring-closing metathesis reactions mediated by various supported Ru carbenes, it is demonstrated that free Ru carbene intermediates in solution can be scavenged by support-bound styrene ether ligands prior to the onset of competing transition metal decomposition. The observations detailed herein provide rigorous evidence that the initially proposed release/return mechanism is, at least partially, operative. The present investigations shed light on a critical aspect of the mechanism of an important class of Ru-based metathesis complexes (those bearing a bidentate styrene ether ligand).
引用
收藏
页码:4510 / 4517
页数:8
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