Copper-catalyzed radical cascade cyclization for synthesis of CF3-containing tetracyclic benzimidazo[2,1-a]iso-quinolin-6(5H)-ones

2021 ◽  
Author(s):  
Kai Sun ◽  
Guofeng Li ◽  
Sa Guo ◽  
Zhiguo Zhang ◽  
Guisheng Zhang
Keyword(s):  
Cascade Cyclization ◽  
Radical Cascade ◽  
Tetracyclic Core

A practical copper-catalyzed radical cascade carbocyclization reaction was developed for the preparation of a variety of structurally diverse CF3-containing tetracyclic core benzimidazo[2,1-a]isoquinoline-6(5H)-ones.

Fe-Catalyzed Conjunctive Cross-Couplings of Unactivated Alkenes with Grignard Reagents

2020 ◽  
Author(s):  
Lei Liu ◽  
Wes Lee ◽  
Cassandra R. Youshaw ◽  
Mingbin Yuan ◽  
Michael B. Geherty ◽  
...  
Keyword(s):  
Functional Groups ◽  
Cross Coupling ◽  
Alkyl Halides ◽  
Grignard Reagents ◽  
Turnover Frequency ◽  
Diverse Range ◽  
Cascade Cyclization ◽  
Radical Cascade

The first iron-catalyzed three-component cross-coupling of unactivated olefins with alkyl halides and Grignard reagents is reported. The reaction operates under fast turnover frequency and tolerates a diverse range of sp2-hybridized nucleophiles, alkyl halides, and unactivated olefins bearing diverse functional groups to yield the desired 1,2-alkylarylated products with high regiocontrol. Further, we demonstrate that this protocol is amenable for the synthesis of new (hetero)carbocycles including tetrahydrofurans and pyrrolidines via a three-component radical cascade cyclization/arylation that forges three new C-C bonds.

Eosin Y photoredox catalyzed net redox neutral reaction for regiospecific annulation to 3-sulfonylindoles via anion oxidation of sodium sulfinate salts

2018 ◽  
Vol 16 (4) ◽  
pp. 536-540 ◽  
Author(s):  
Rajendra S. Rohokale ◽  
Shrikant D. Tambe ◽  
Umesh A. Kshirsagar
Keyword(s):  
Visible Light ◽  
Eosin Y ◽  
Cascade Cyclization ◽  
Neutral Reaction ◽  
Neutral Process ◽  
Radical Cascade

An eosin Y photoredox catalyzed net redox neutral process for 3-sulfonylindoles via the anionic oxidation of sodium sulfinate salts and its radical cascade cyclization with 2-alkynyl-azidoarenes was developed with visible light as a mediator.

Iron-catalyzed radical cascade cyclization of oxime esters with isocyanides: synthesis of 1-cyanoalkyl isoquinolines and 6-cyanoalkyl phenanthridines

2021 ◽  
Vol 19 (39) ◽  
pp. 8597-8606
Author(s):  
Dengqi Xue ◽  
Rongqi Liu ◽  
Denggao Zhang ◽  
Ning Li ◽  
Yijie Xue ◽  
...  
Keyword(s):  
Cascade Cyclization ◽  
Radical Cascade

An iron-catalyzed radical cascade cyclization of oxime esters with isocyanides for the synthesis of 1-cyanoalkyl isoquinolines and 6-cyanoalkyl phenanthridines has been developed.

Catalytic Radical Cascade Cyclization of Alkene-Tethered Enones to Fused Bicyclic Cyclopropanols

2021 ◽  
Author(s):  
Ying Xie ◽  
Wei Huang ◽  
Song Qin ◽  
Shaomin Fu ◽  
Bo Liu
Keyword(s):  
Hydrogen Atom ◽  
Cascade Reaction ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Trimethyl Borate ◽  
Cascade Cyclization ◽  
Radical Cascade ◽  
Privileged Scaffolds

An unprecedented hydrogen atom transfer-triggered intramolecular cascade reaction between alkene and enone is developed, using Fe(acac)3, PhSiH2(Oi-Pr) and trimethyl borate, to efficiently construct cis-fused bicyclic cyclopropanols, privileged scaffolds often found...

Electrochemical oxidative radical cascade cyclization of olefinic amides and thiophenols towards the synthesis of sulfurated benzoxazines, oxazolines and iminoisobenzofurans

2021 ◽  
Author(s):  
Fangling Lu ◽  
Jie Xu ◽  
Hao Li ◽  
Ke Wang ◽  
Dandan Ouyang ◽  
...  
Keyword(s):  
Cascade Cyclization ◽  
Radical Cascade

Heterocycles containing N and O are important structures in pharmaceuticals, agrochemicals and functional molecules.

Copper-catalyzed radical cascade cyclization of 2-(allyloxy)arylaldehydes towards chroman-4-one derivatives

2021 ◽  
pp. 153605
Author(s):  
Wenbin Guo ◽  
Linlin Gui ◽  
Xin Chen ◽  
Zhijun Dai ◽  
Liping Wang ◽  
...  
Keyword(s):  
Cascade Cyclization ◽  
Radical Cascade

Alkaloid Synthesis: (-)-Aurantioclavine (Stoltz), (-)-Esermethole (Nakao/Hiyama/ Ogoshi), (-)-Kainic Acid (Tomooka), Dasycarpidone (Bennasar), (-)-Cephalotaxine (Ishibashi) and Lysergic Acid (Fujii/Ohno)

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Kainic Acid ◽  
Absolute Configuration ◽  
Lysergic Acid ◽  
Ni Catalyst ◽  
Cascade Cyclization ◽  
Alkaloid Synthesis ◽  
Radical Cascade ◽  
The Absolute ◽  
The University ◽  
Stereogenic Center

Intriguing strategies have been developed for the stereocontrolled assembly of complex alkaloid structures. Brian M. Stoltz of Caltech prepared (J. Am. Chem. Soc. 2008, 130, 13745) the enantiomerically-pure alcohol precursor to the secondary amine 1 by enantioselective oxidation of the racemic alcohol. Intramolecular Mitsunobu coupling of 1 then led to (-)-Aurantioclavine 3. Yoshiaki Nakao and Tamejiro Hiyama of Kyoto University and Sensuke Ogoshi of Osaka University developed (J. Am. Chem. Soc. 2008, 130, 12874) an enantioselective Ni catalyst for the cyclization of 4 to 5. Oxidation and cyclization then delivered (-)-Esermethole 6. Although the sulfonamide 7 appears to be prochiral, in fact its two most stable conformations are bent, and enantiomers of each other, with a significant barrier for interconversion. Katsuhiko Tomooka of Kyushu University separated (Tetrahedron Lett. 2008, 49, 6327) the enantiomers of 7, then carried the enantiomercially-pure 7 on, by Pd-catalyzed Cope rearrangement, to 8 and so to (-)-Kainic Acid 9. M.-Lluïsa Bennasar of the University of Barcelona prepared (J. Org. Chem. 2008, 73, 9033) the acyl selenide 11 from the indole 10. While the radical derived from 11 might have been expected to undergo 5-exo cyclization, in the event the 6-endo mode dominated, to give Dasycarpidone 12 and its diastereomer. Hiroyuki Ishibashi of Kanazawa University showed (Organic Lett. 2008, 10, 4129) that the radical cascade cyclization of the enamine 13, derived from diethyl tartrate, proceeded with remarkable diastereocontrol, to give 14. The amide 14 was converted to (-)-Cephalotaxine 15. Nobutaka Fujii and Hiroaki Ohno, also of Kyoto University, used (Organic Lett. 2008, 10, 5239) a Pd catalyst to mediate the cascade cyclization of 16 to 17. Although 16 has two stereogenic centers, including the allene, it is the aminated stereogenic center of 17 that sets the absolute configuration of the product Lysergic Acid 18. One intermediate in the conversion of 16 to the tetracyclic 17 is the tricyclic π-allyl Pd complex. If all the material could be channeled through that pathway, there is a good chance that the chiral Trost catalyst could effectively control the absolute configuration of the aminated stereogenic center as it is formed, leading to the enantiomerically enriched product 18.

Silver-catalyzed radical cascade cyclization of 1,3-diarylpropynones with 1,3-dicarbonyl compounds to access 2-dicarbonyl indenones

2020 ◽  
Vol 61 (13) ◽  
pp. 151679
Author(s):  
Zhenhua Li ◽  
Yao Ma ◽  
Jinjing Qin ◽  
Zhiyong Tan ◽  
Xiaomeng Sun ◽  
...  
Keyword(s):  
Dicarbonyl Compounds ◽  
Cascade Cyclization ◽  
Radical Cascade

Visible-Light-Induced Radical Cascade Cyclization: Synthesis of (20S )-Camptothecin, SN-38 and Irinotecan

2018 ◽  
Vol 36 (11) ◽  
pp. 1035-1040 ◽  
Author(s):  
Yao Yuan ◽  
Wuheng Dong ◽  
Xiaoshuang Gao ◽  
Xiaomin Xie ◽  
Dennis P. Curran ◽  
...  
Keyword(s):  
Visible Light ◽  
Cascade Cyclization ◽  
Radical Cascade

A radical cyclization cascade of 2-alkynylbenzonitriles with sodium arylsulfinates

2018 ◽  
Vol 16 (42) ◽  
pp. 7959-7963 ◽  
Author(s):  
Bang Zhou ◽  
Wenqi Chen ◽  
Yuzhong Yang ◽  
Yuan Yang ◽  
Guobo Deng ◽  
...  
Keyword(s):  
Radical Cyclization ◽  
Efficient Approach ◽  
Cascade Cyclization ◽  
Radical Cascade

We report an efficient approach to synthesize sulfonated indenones via a radical cascade cyclization of 2-alkynylbenzonitriles with sodium arylsulfinates.

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