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[摘要]:The activity and stereoselectivity of phosphane- and N-heterocyclic carbene (NHC)-containing ruthenium benzylidene complexes have been evaluated in macrocyclic ring-closing olefin metathesis to produce unsaturated lactones and lactams. The success of the macrocyclization depends on the nature of the ligand (phosphane or N-heterocyclic carbene) on the ruthenium center and on the NHC properties. As for stereoselectivity, E/Z ratios seem to be influenced not only by the nature of the ruthenium catalyst but also by the thermodynamic stabilities of the resulting unsaturated macrocycles, as confirmed by theoretical results. |
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