CuO/SiO2 as a simple, effective and recoverable catalyst for alkylation of indole derivatives with diazo compounds
作者:José M. Fraile、Karel Le Jeune、José A. Mayoral、Nicoletta Ravasio、Federica Zaccheria
DOI:10.1039/c3ob40264a
日期:——
The purely inorganic copper oxide on silica catalyzes the reaction of methyl phenyldiazoacetate with N-methyl indole under mild reaction conditions, giving the alkylation (formally a C–H insertion) in position 3, and the catalyst can be recovered and reused at least in 5 consecutive runs with only minor loss in activity. The scope of the reaction includes various diazo compounds and indole or pyrrole derivatives leading to alkylation or cyclopropanation depending on the heterocycle structure. An alternative mechanism, without reduction of Cu(II) to Cu(I), is proposed on the basis of the obtained results.
二氧化硅上的纯无机氧化铜可在温和的反应条件下催化苯基重氮乙酸甲酯与 N-甲基吲哚的反应,在第 3 位发生烷基化(形式上为 C-H 插入),催化剂可回收并重复使用至少 5 次,且活性仅略有下降。反应范围包括各种重氮化合物、吲哚或吡咯衍生物,根据杂环结构的不同,可导致烷基化或环丙烷化。根据所获得的结果,提出了一种不将 Cu(II) 还原成 Cu(I) 的替代机制。