title: Aromatic C-H Bond Functionalization Induced by Electrochemically in Situ Generated Tris(p-bromophenyl)aminium Radical Cation: Cationic Chain Reactions of Electron-Rich Aromatics with Enamides.
abstract: An effective Friedel-Crafts alkylation reaction of electron-rich aromatics with N-vinylamides, induced by electrochemically in situ-generated TBPA radical cation, has been developed; the resulting adducts are produced in good to excellent yields. In the "ex-cell" type electrolysis, TBPA is transformed to its oxidized form in situ and subsequently employed as an electron transfer reagent to initiate a cationic chain reaction. An easily recoverable and reusable polymeric ionic liquid-carbon black (PIL-CB) composite was also utilized as a supporting electrolyte for the electrochemical generation of TBPA cation radical, without sacrificing efficiency or stability after four electrolyses. Cyclic voltammetry analysis and the results of control experiments demonstrate that the reaction of electron-rich aromatics and N-vinylamides occurs via a cationic chain reaction, which takes place though an oxidative activation of a C-H bond of electron-rich aromatics instead of oxidation of the N-vinylamide as previously assumed.
authors.affiliation: College of Life Science & Bioengineering, Beijing University of Technology , Beijing 100124, China.
authors.forename: Long-Ji
authors.initials: LJ
authors.lastname: Li
authors.affiliation: College of Life Science & Bioengineering, Beijing University of Technology , Beijing 100124, China.
authors.forename: Yang-Ye
authors.initials: YY
authors.lastname: Jiang
authors.affiliation: Department of Chemistry & Biochemistry, University of California at Santa Barbara , Santa Barbara, California 93106, United States.
authors.forename: Chiu Marco
authors.initials: CM
authors.lastname: Lam
authors.affiliation: College of Life Science & Bioengineering, Beijing University of Technology , Beijing 100124, China.
authors.forename: Cheng-Chu
authors.initials: CC
authors.lastname: Zeng
authors.affiliation: College of Life Science & Bioengineering, Beijing University of Technology , Beijing 100124, China.
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Hu
authors.affiliation: Department of Chemistry & Biochemistry, University of California at Santa Barbara , Santa Barbara, California 93106, United States.
authors.forename: R Daniel
authors.initials: RD
authors.lastname: Little