Reactions and Mechanistic Studies of Rhenium-Catalyzed Insertion of α,β-Unsaturated Carbonyl Compounds into a C-H Bond
Reactions and Mechanistic Studies of Rhenium-Catalyzed Insertion of α,β-Unsaturated Carbonyl Compounds into a C-H Bond
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DOI：
10.1246/bcsj.81.1393
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发表时间：
2008-11-15
影响因子：
4
通讯作者：
Takai, Kazuhiko
中科院分区：
文献类型：
--
作者：
Kuninobu, Yoichiro;Nishina, Yuta;Takai, Kazuhiko
铼配合物[ReBr(CO)(3)(thf)](2)，催化α， β -不饱和羰基化合物插入具有含氮导向基团的芳香化合物的C-H键。在该反应中，Re-2(CO)（10）也可用作催化剂。当亚胺作为芳香族底物时，序贯环化进行，独立衍生物得到良好到优异的收率。这种反应活性与钌和铑配合物的反应活性形成鲜明对比，钌和铑配合物通常用作不饱和分子插入C-H键反应的催化剂。对反应机理的研究表明，铼催化剂促进芳香化合物的C-H键活化，α、β -不饱和羰基化合物插入Re-C键，以及分子内亲核环化，然后是还原消除和胺的消除。
A rhenium complex, [ReBr(CO)(3)(thf)](2), catalyzes the insertion of alpha,beta-unsaturated carboryl compounds into a C-H bond of aromatic compounds having nitrogen-containing directing groups. In this reaction, Re-2(CO)(10) call also be used as a catalyst. When imines are employed as the aromatic substrates, sequential cyclization proceeds and indene derivatives are obtained in good to excellent yields. This reactivity is ill contrast to those of ruthenium and rhodium complexes, which are usually used as catalysts in the insertion reactions of unsaturated molecules into a C-H bond. Investigations oil the reaction mechanism indicate that the rhenium catalyst promotes C-H bond activation of aromatic compounds, the insertion of alpha,beta-unsaturated carbonyl compounds into a Re-C bond, and intramolecular nucleophilic cyclization followed by reductive elimination and the elimination of an amine.