Cp*-Free Cobalt-Catalyzed C–H Activation/Annulations by Traceless <i>N</i>,<i>O</i>-Bidentate Directing Group: Access to Isoquinolines
作者:Xiao-Cai Li、Cong Du、He Zhang、Jun-Long Niu、Mao-Ping Song
DOI:10.1021/acs.orglett.9b00866
日期:2019.4.19
N,O-Bidentate directing-enabled, traceless heterocycle synthesis is described via Cp*-free cobalt-catalyzedC–Hactivation/annulation. The weakly coordinating nature of the carboxylic acid was employed for the preparation of isoquinolines. Meanwhile, the N–Obond of the α-imino-oxy acid can serve as an internaloxidant. Terminal as well as internalalkynes can be efficiently applied to the catalytic
<i>N</i>-Tosylhydrazone directed annulation <i>via</i> C–H/N–N bond activation in Ru(<scp>ii</scp>)/PEG-400 as homogeneous recyclable catalytic system: a green synthesis of isoquinolines
作者:Dewal S. Deshmukh、Bhalchandra M. Bhanage
DOI:10.1039/c8ob01082j
日期:——
of isoquinolines using Ru(II)/PEG-400 as a homogeneous recyclable catalytic system has been demonstrated. N-Tosylhydrazone, a rarely explored directing group, has been successfully employed for an annulation type of reaction with alkynes viaC–H/N–N activation. A short reaction time with a simple extraction procedure, a wide substrate scope with high yields of products, easily prepared substrates, biodegradable
Cobalt(III)-Catalyzed Dehydrative [4+2] Annulation of Oxime with Alkyne by CH and NOH Activation
作者:Malay Sen、Deepti Kalsi、Basker Sundararaju
DOI:10.1002/chem.201503643
日期:2015.10.26
Efficient, scalable cobalt‐catalyzed redox‐neutral [4+2] annulation of readily available oximes and alkyne is reported. The developed synthetic methodology is widely applicable and tolerates various functional groups including heterocycles. A stable Cp*CoIII neutral complex is employed as the catalyst for this redox‐neutral [4+2] annulation reaction, which progresses smoothly by way of a reversible
据报道,高效,可扩展的钴催化的氧化还原中性[4 + 2]环化易于获得的肟和炔烃。所开发的合成方法学广泛适用,并能耐受包括杂环在内的各种官能团。稳定的Cp * Co III中性络合物用作该氧化还原-中性[4 + 2]环化反应的催化剂,该反应通过可逆的环金属化反应顺利进行,而无需任何外部氧化剂,仅产生水作为副产物。
Rhodium-Catalyzed One-Pot Access to N-Polycyclic Aromatic Hydrocarbons from Aryl Ketones through Triple C–H Bond Activations
A Rh-catalyzed pot and step economic synthesis of aza-polycyclic aromatic hydrocarbons (N-PAHs) from readily available aryl ketones and alkynes has been disclosed. Additionally, a novel synthetic application of the well-known aminating reagent hydroxylamine-O-sulfonic acid (HOSA) has been explored as an in situ redox-neutral directinggroup for the formation of N-PAHs via isoquinoline. Multiple bond
Rhodium-Catalyzed Synthesis of Isoquinolines and Indenes from Benzylidenehydrazones and Internal Alkynes
作者:Xiao-Cheng Huang、Xu-Heng Yang、Ren-Jie Song、Jin-Heng Li
DOI:10.1021/jo402497v
日期:2014.2.7
presented for the selective assembly of isoquinolines and indenes by rhodium-catalyzed tandem cyclization of benzylidenehydrazones with internal alkynes. This method involves the selective cleavage of the N–N bond and the C═N bonds and is dependent on the substituents of the benzylidenehydrazone.