Well‐Defined, Versatile and Recyclable Half‐Sandwich Nickelacarborane Catalyst for Selective Carbene‐Transfer Reactions
作者:Linghua Wang、Saima Perveen、Yizhao Ouyang、Shuai Zhang、Jiao Jiao、Gang He、Yong Nie、Pengfei Li
DOI:10.1002/chem.202005014
日期:2021.3.26
accessible nickel(II)‐based complexes have been rarely used. Herein, an air‐stable nickel(II)‐carborane complex is reported as a well‐defined, versatile and recyclable catalyst for selective carbene transfer reactions with low catalyst loading undermildconditions. This catalyst is effective for several types of reactions including diastereoselective cyclopropanation, epoxidation, selective X−H insertions
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.
Ruthenium Catalyzed Directing Group-Free C2-Selective Carbenoid Functionalization of Indoles by α-Aryldiazoesters
作者:Wai-Wing Chan、Shing-Hin Yeung、Zhongyuan Zhou、Albert S. C. Chan、Wing-Yiu Yu
DOI:10.1021/ol9028226
日期:2010.2.5
A directing group-free approach for C2-selective carbenoid functionalization of NH-indoles is presented. Using [RuCl2(p-cymene)](2) as catalyst and alpha-aryldiazoesters as carbenoid source, 2-alkylated indoles were obtained in up to 96% isolated yield. Similarly, a regioselective carbenoid functionalization of NH-pyrroles was also achieved.