Rhodium-catalyzed cyclization of acceptor-substituted biphenyl α-diazoketones: a study of the substitution effect on chemoselectivity
| Autor: | Jia-Liang Zhu, Yi-Jung Chiang, Kuo-Hsin Chen |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Sulfonyl
chemistry.chemical_classification Biphenyl 010405 organic chemistry Organic Chemistry Electrophilic aromatic substitution 010402 general chemistry 01 natural sciences Biochemistry Medicinal chemistry Cycloaddition 0104 chemical sciences chemistry.chemical_compound chemistry Diazo Carboxylate Physical and Theoretical Chemistry Chemoselectivity Selectivity |
| Zdroj: | Organic & Biomolecular Chemistry. 16:8353-8364 |
| ISSN: | 1477-0539 1477-0520 |
| DOI: | 10.1039/c8ob01489b |
| Popis: | A range of biphenyl α-diazoketones containing various electron-withdrawing groups (EWG = COCH3, CN, CO2Et, COPh, SO2CH3, SO2Ph) on diazo carbon has been investigated for rhodium(ii)-catalyzed intramolecular cyclization. Among which, the α-acetyl, carboxylate and cyano substituted substrates show markedly different selectivity between aromatic substitution and aromatic cycloaddition processes, affording phenanthrol and/or benz[α]azulenone products in varying ratios. The selectivity is mainly directed by α-substitutions, and is also possibly influenced by the substituents on the biphenyl ring. Moreover, high chemoselectivity for aromatic substitution over cycloaddition is observed for the α-benzoyl and sulfonyl substituted substrates. But in addition to phenanthrols, these reactions produce aromatic ketones and/or 1,2-diketones as unprecedented products obtained from diazo precursors. Mechanistic rationales are given in the report. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|