Electrochemical [4+2] Annulation‐Rearrangement‐Aromatization of Styrenes: Synthesis of Naphthalene Derivatives

• Published in: Angewandte Chemie Vol. 131; no. 20; pp. 6828 - 6832
• Main Authors: Ma, Yueyue, Lv, Jufeng, Liu, Chengyu, Yao, Xiantong, Yan, Guoming, Yu, Wei, Ye, Jinxing
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 13.05.2019
• Subjects: [4+2]-Anellierung; Aromatisierung; Chemical industry; Chemical reactions; Chemistry; Cycloaddition; Derivatives; Electrochemistry; Electrolysis; Metals; Naphthalene; Naphthaline; Organic chemistry; Oxidants; Oxidizing agents; Styrene; Styrenes; Styrole; Substrates; Umlagerungen
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.201902315

We report the first electrochemical strategy to synthesize functionalized naphthalene derivatives through [4+2] annulation—rearrangement–aromatization from styrenes under mild conditions. The electrolysis does not require metals, oxidants and high valence substrates, indicating the atom and step‐economy ideals. The dehydrodimer produced through [4+2] cycloaddition of 4‐methoxy α‐methyl styrene is isolated and proved to be the key intermediate for the following oxydehydrogenation to form carbon cation, which undergoes rearrangement–aromatization to afford the final products. This reaction represents a powerful access to construct multi‐substituted naphthalene blocks in a single step. Ein elektrochemisches Protokoll zum Aufbau von Naphthalinen ohne Oxidationsmittel, Metalle und hochvalente Reaktanten wurde entwickelt. Das durch elektroinduzierte [4+2]‐Anellierung erzeugte Dehydrodimer ist das Schlüsselintermediat, das Oxydehydrierung und Umlagerung/Aromatisierung zum Endprodukt eingeht.