Organometallic Synthesis and Catalysis Lab, Organic Chemistry Division, CSIR - National Chemical Laboratory (CSIR - NCL), Dr. Homi Bhabha Road, Pune, 411 008, India.
Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002, India.
Chem Asian J. 2022 Aug 1;17(15):e202200414. doi: 10.1002/asia.202200414. Epub 2022 Jun 10.
Iron-catalyzed dimerization of various isatin derivatives is described for the efficient synthesis of 3,3'-biindolinylidene-diones (isoindigos). The reaction provides easy access to self-coupled and cross-coupled 3,3'-indolinylidene-diones that have high relevance to biology and materials. This Fe(0)- or Fe(II)-catalyzed dimerization reaction tolerates a wide range of functionalities, such as fluoro, chloro, bromo, alkenyl, nitrile, ether, ester, pyrrolyl, indolyl and carbazolyl groups, including cyclic and acyclic alkyls as well as an alkyl-bearing fatty-alcohol moiety. Especially, the coupling between two distinct isatins provided excellent selectivity for the cross-dimerization with trace of self-couplings. The single-crystal X-ray diffraction study established the molecular structure of eight dimerized products. A preliminary mechanistic study of the Fe-catalyzed dimerization supported the radical pathway for the reaction.
描述了铁催化的各种色胺衍生物的二聚反应，用于高效合成 3,3'-联吲哚啉二酮（异吲哚）。该反应提供了易于获得自偶联和交叉偶联的 3,3'-吲哚啉二酮的途径，这些二酮在生物学和材料学上具有重要意义。这种 Fe(0)或 Fe(II)催化的二聚反应能够容忍广泛的官能团，如氟、氯、溴、烯基、腈、醚、酯、吡咯基、吲哚基和咔唑基，包括环状和无环烷基以及带有烷基的脂肪醇部分。特别是，两个不同色胺之间的偶联为交叉二聚提供了优异的选择性，痕量的自偶联产物。通过单晶 X 射线衍射研究确定了八个二聚化产物的分子结构。对 Fe 催化二聚反应的初步机理研究支持了该反应的自由基途径。
