C–H Activation Guided by Aromatic N–H Ketimines: Synthesis of Functionalized Isoquinolines Using Benzyl Azides and Alkynes
摘要:
Aromatic N-H ketimines were in situ generated from various benzylic azides by ruthenium catalysis for the subsequent Rh-catalyzed annulation reaction with alkynes to give the corresponding isoquinolines. In contrast to conventional synthetic methods for aromatic NH ketimines, our protocol works under mild and neutral conditions, which enabled the synthesis of isoquinolines having various functionalities such as carbonyl, ester, alkenyl, and ether groups. In addition, the imidates generated from alpha-azido ethers were successfully used for the synthesis of 1-alkoxyisoquinolines.
Electrochemical Access to Aza‐Polycyclic Aromatic Hydrocarbons: Rhoda‐Electrocatalyzed Domino Alkyne Annulations
作者:Wei‐Jun Kong、Zhigao Shen、Lars H. Finger、Lutz Ackermann
DOI:10.1002/anie.201914775
日期:2020.3.27
Nitrogen-doped polycyclicaromatichydrocarbons (aza-PAHs) have found broad applications in material sciences. Herein, a modular electrochemical synthesis of aza-PAHs was developed via a rhodium-catalyzed cascade C-H activation and alkyne annulation. A multifunctional O-methylamidoxime enabled the high chemo- and regioselectivity. The isolation of two key rhodacyclic intermediates made it possible
An efficient double C–N bond formation sequence to prepare highly substituted quinazolines utilizing benzimidates and dioxazolones under the catalytic redox-neutral [Cp*RhCl2]2/AgBF4 system, where dioxazolones could work as an internal oxidant to maintain the catalytic cycle, is reported. N-Unsubstituted imine not only acts as a directing group but also functions as a nucleophile in postcoupling cyclization
An Inverse Electron Demand Azo-Diels–Alder Reaction of <i>o</i>-Quinone Methides and Imino Ethers: Synthesis of Benzocondensed 1,3-Oxazines
作者:Dmitry V. Osipov、Vitaly A. Osyanin、Guzel’ D. Khaysanova、Elvira R. Masterova、Pavel E. Krasnikov、Yuri N. Klimochkin
DOI:10.1021/acs.joc.8b00692
日期:2018.4.20
the reactions of o-quinone methide precursors with iminoethers. The reaction provides a versatile route to substituted 1,3-benzoxazines. The proposed reaction mechanism involves the generation of the o-quinone methide intermediates, imino-Diels–Alder reaction, and elimination. This cascade process is a rare example of the participation of iminoethers as dienophiles.
Mechanism of generation of <i>closo</i>-decaborato amidrazones. Intramolecular non-covalent B–H⋯π(Ph) interaction determines stabilization of the configuration around the amidrazone CN bond
作者:Valeria K. Burianova、Dmitrii S. Bolotin、Alexander S. Mikherdov、Alexander S. Novikov、Pennie Petrus Mokolokolo、Andreas Roodt、Vadim P. Boyarskiy、Dmitry Dar’in、Mikhail Krasavin、Vitalii V. Suslonov、Andrey P. Zhdanov、Konstantin Yu. Zhizhin、Nikolay T. Kuznetsov
DOI:10.1039/c8nj01018h
日期:——
consecutive incorporation of two Nu(H) nucleophiles, with the second responsible for a subsequent rapid proton exchange. The second possible mechanism assumes a pre-formation of a dinuclear [Nu(H)]2 species which subsequently proceeds with the nucleophilic attack on the boron cluster. The activation parameters for hydrazones indicate a small dependence on bondformation [ΔH‡ = 6.8–15 kJ mol−1], but significantly
Synthesis of isoquinolines based on efficient C–C and C–N bond formation through Rh(III)-catalyzed C–H activation and subsequent intramolecular cyclization is reported. Diazodiesters serving as a C2 source in the newly formed heterocycles are first demonstrated. Additionally, the Rh(III)-catalyzed direct C–H activation/cyclization of benzimidates with diazoketoesters is also described.