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
protocol for direct C–H alkylation and acylation of N-heterocycles, using readily accessible carboxylic acids as radical precursors under visible-light irradiation without a photocatalyst and an additional acid additive, has been developed. This protocol provides expedient access to substituted N-heterocycles under mild and metal-free conditions. Mechanistic experiments indicate that this reaction proceeds
Highly Efficient Synthesis of Isoquinolines via Nickel-Catalyzed Annulation of 2-Iodobenzaldimines with Alkynes: Evidence for Dual Pathways of Alkyne Insertion
作者:Rajendra Prasad Korivi、Chien-Hong Cheng
DOI:10.1021/ol0519994
日期:2005.11.1
[reaction: see text] A wide range of substituted isoquinolines were synthesized via a highly efficient nickel-catalyzed annulation of the tert-butyl imines of 2-iodobenzaldehydes and various alkynes; examination of the regiochemistry of isoquinolines synthesized indicates that there are two different alkyne insertion pathways for the catalytic reactions.
Cobalt-Catalyzed Selective Synthesis of Isoquinolines Using Picolinamide as a Traceless Directing Group
作者:Changsheng Kuai、Lianhui Wang、Bobin Li、Zhenhui Yang、Xiuling Cui
DOI:10.1021/acs.orglett.7b00702
日期:2017.4.21
first been employed as a traceless directing group for the cobalt-catalyzed oxidative annulation of benzylamides with alkynes to synthesize isoquinolines throughC–H/N–H bonds activation. Oxygen is used as a terminal oxidant. This protocol exhibits good functional group tolerance and excellent regioselectivity. Both terminal and internalalkynes can be efficiently applied to this catalytic system as substrates
Palladium-catalyzed enolate arylation as a key C–C bond-forming reaction for the synthesis of isoquinolines
作者:Ben S. Pilgrim、Alice E. Gatland、Carlos H. A. Esteves、Charlie T. McTernan、Geraint R. Jones、Matthew R. Tatton、Panayiotis A. Procopiou、Timothy J. Donohoe
DOI:10.1039/c5ob02320c
日期:——
those that give rise to the traditionally difficult to access electron-deficient isoquinoline skeletons. These two synthetic operations can be combined to give a three-component, one-pot isoquinoline synthesis. Alternatively, cyclization of the intermediates with hydroxylamine hydrochloride engenders direct access to isoquinoline N-oxides; and cyclization with methylamine, gives isoquinolinium salts. Significant