Facile Synthesis of 3-Aryloxindoles via Brønsted Acid Catalyzed Friedel–Crafts Alkylation of Electron-Rich Arenes with 3-Diazooxindoles
作者:Changwei Zhai、Dong Xing、Changcheng Jing、Jun Zhou、Chengjin Wang、Dongwei Wang、Wenhao Hu
DOI:10.1021/ol5010752
日期:2014.6.6
A simple metal-free method for the synthesis of 3-aryloxindoles via Brønsted acidcatalyzed aromatic C–H functionalization of electron-rich arenes with 3-diazooxindoles is developed. In the presence of a catalytic amount of TfOH, a series of 3-aryloxindoles are synthesized as single regioisomers in good to excellent yields. This transformation is proposed to proceed through acid-catalyzed protonation
Synthesis of Isatin‐Hydrazones from 3‐Diazo Oxindoles and Sulfoxonium Ylides under Catalyst‐ and Additive‐Free Conditions
作者:Yu Tian、Zunting Zhang、Tao Wang
DOI:10.1002/ejoc.202100060
日期:2021.3.12
A facile synthesis of isatin‐hydrazones from 3‐diazo oxindoles and sulfoxonium ylides undercatalyst‐ and additive‐freeconditions was reported. The reaction has a broad substrate scope, affording a variety of products with good yields (42–95 %). The mechanism for the formation of the products was also investigated.
Carbeneinsertion into the C(sp2)−H bonds of internal alkenes was enabled in air by HFIP (1,1,1,3,3,3-hexafluoro-2-propanol) as both the mediator and solvent through its cooperation with borane B(C6F5)3 as the catalyst. 3-Diazooxindoles and 3-diazoindolin-2-imines were amenable to work as the carbene precursors, and α-oxo ketene dithioacetals acted as the internal alkenes at ambient temperature. The
Zinc(II)-catalyzed [2+2+1] annulation of internal alkenes, diazooxindoles, and isocyanates was successfully developed for the construction of multisubstituted spirooxindoles. This multicomponent transformation involves in situ generation of a sulfur-containing spirocyclic intermediate from the [4+1] annulation of diazooxindole to sulfonyl isocyanate, which subsequently reacts as a 1,3-dipole with the
3-allyl/3-allenyl-3-(thio)oxindole core remains a challenge in organic synthesis. Herein, we report a novel Rh2(esp)2 catalytic Doyle–Kirmse reaction to furnish the oxindole core, bearing unbiased NH as well as a quaternary stereogenic center at the 3-position, in good to excellent yields under mild conditions. These reactions are concise, practical, atom-economic, and highly efficient, and feature a TON