Tandem catalysis of ring-closing metathesis/atom transfer radical reactions with homobimetallic ruthenium–arene complexes

Beilstein Journal of Organic Chemistry

Lionel Delaude¹  Xavier Sauvage¹  Yannick Borguet¹  Albert Demonceau¹  Guillermo Zaragoza² 

[1] Laboratory of Macromolecular Chemistry and Organic Catalysis, Institut de Chimie (B6a), Université de Liège, Sart-Tilman par 4000 Liège, Belgium;Unidade de Raios X, Edificio CACTUS, Universidade de Santiago de Compostela, Campus Vida, 15782 Santiago de Compostela, Spain;

关键词: Grubbs catalyst;    indenylidene ligands;    Kharasch reaction;    microwave heating;    olefin metathesis;   

DOI  :  10.3762/bjoc.6.133

来源: DOAJ

【 摘 要 】

The tandem catalysis of ring-closing metathesis/atom transfer radical reactions was investigated with the homobimetallic ruthenium–indenylidene complex [(p-cymene)Ru(μ-Cl)3RuCl(3-phenyl-1-indenylidene)(PCy3)] (1) to generate active species in situ. The two catalytic processes were first carried out independently in a case study before the whole sequence was optimized and applied to the synthesis of several polyhalogenated bicyclic γ-lactams and lactones from α,ω-diene substrates bearing trihaloacetamide or trichloroacetate functionalities. The individual steps were carefully monitored by 1H and 31P NMR spectroscopies in order to understand the intimate details of the catalytic cycles. Polyhalogenated substrates and the ethylene released upon metathesis induced the clean transformation of catalyst precursor 1 into the Ru(II)–Ru(III) mixed-valence compound [(p-cymene)Ru(μ-Cl)3RuCl2(PCy3)], which was found to be an efficient promoter for atom transfer radical reactions under the adopted experimental conditions.

【 授权许可】

Unknown