Palladium-Catalyzed Intramolecular Fujiwara-Hydroarylation: Synthesis of Benzo[a]phenazines Derivatives

Sonu Kumar, Rakesh K. Saunthwal, Mohammad Mujahid, Trapti Aggarwal, Akhilesh K. Verma*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

21 Citations (Scopus)

Abstract

An atom-economical Pd-catalyzed approach for the synthesis of benzophenazine derivatives using substituted 2-aryl-3-(aryl/alkylethynyl) quinoxaline in the presence of trifluoroacetic acid at 65 °C has been described. The chemistry involves in situ generation of cationic Pd(II) species, which functionalized the aromatic C-H bonds via electrophilic metalation followed by concomitant intramolecular trans-insertion of C-C triple bond to aryl-Pd complex. The results were supported by various control experiments including with electron-deficient arenes and deuterium labeling studies. The deuterium labeling studies supports electrophilic palladation of aromatic C-H over activation of C-C triple bond of alkyne. The structure of synthesized compounds was further confirmed by X-ray crystallography studies. This catalytic protocol has been efficiently applied for novel synthesis of highly functionalized benzo fused phenazines.

Original languageEnglish
Pages (from-to)9912-9923
Number of pages12
JournalJournal of Organic Chemistry
Volume81
Issue number20
DOIs
Publication statusPublished - 21 Oct 2016

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