Aurated Aryl Cations as Halogen Abstractors – Easy Access to 1-Halogenated Naphthalenes
作者:Michael Schukin、Thomas Wurm、Janina Bucher、Martin C. Dietl、Caroline J. Aschendorf、Matthias Rudolph、Frank Rominger、Jürgen Graf、A. Stephen K. Hashmi
DOI:10.1021/acscatal.3c03907
日期:2024.2.2
1,5-Diynes bearing two terminal alkyne functionalities are converted into highly reactive naphthyl cation intermediates by a gold(I) catalyst with a sterically demanding ligand. This highly electrophilic intermediate is utilized for the abstraction of halogens from appropriate solvents (e.g., DCE).
Regioselective Haloaromatization of 1,2-Bis(ethynyl)benzene via Halogen Acids and PtCl<sub>2</sub>. Platinum-Catalyzed 6-π Electrocyclization of 1,2-Bis(1‘-haloethenyl)benzene Intermediates
作者:Ching-Yu Lo、Manyam Praveen Kumar、Hsu-Kai Chang、Shie-Fu Lush、Rai-Shung Liu
DOI:10.1021/jo0518295
日期:2005.12.1
Treatment of 1,2-bis(ethynyl)benzene (1) with aqueous HX (X = Br, I) in hot 3-pentanone (100105 degrees C, 2 h) afforded 1,2-bis(1'-baloethenyl)benzene species 2-Br and 2-I in 98% and 95% yields, respectively. The hydrochlorination of endiyne 1 failed to proceed at elevated temperature but was implemented efficiently by PtCl2 (5 mol %) in hot 3-pentanone (100 degrees C, 2 h) to give 1,2-bis(1'-chloroethenyl)benzene 2-Cl in 80% yield. In the presence of PtCl2 (5 mol %), these halides 2-Cl, 2-Br, and 2-I were subsequently converted to 1-halonaphthalenes 3-Cl, 3-Br, and 3-I in the mother solution via sequential 6-pi electrocyclization and dehalogenation reactions. PtCl2 (5 mol %) also effected direct haloaromatization of endiyne 1 with HX (X = Cl, Br, 1) and gave 1-halonaphthalenes 3-Cl, 3-Br, and 3-I in 64-71% yields. This investigation reports the scope and the regioselectivity of haloaromatization of various enediynes catalyzed by PtCl2.
WO2008/58402
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A Visible Light and Iron‐mediated Carbocationic Route to Polysubstituted 1‐Halonaphthalenes by Benzannulation using Allylbenzenes and Polyhalomethanes
作者:Irwan Iskandar Roslan、Hongwei Zhang、Kian‐Hong Ng、Stephan Jaenicke、Gaik‐Khuan Chuah
DOI:10.1002/adsc.202001249
日期:2021.2.16
A wide array of polysubstituted 1‐bromo and chloronaphthalenes are obtained from coupling of allylbenzenes and polyhalomethanes. The reaction is mediated by iron metal under visible light irradiation and proceeds via a Kharasch addition intermediate followed by intramolecular FeIII mediated Friedel‐Crafts alkylation, with the formation of two Csp2−Csp2 bonds in the process. This method gives easy access