Regiospecific Inverse-Electron-Demand Diels–Alder Reaction of Simultaneously Electrogenerated Diene and Dienophile: An Expeditious Route to Polyfunctionalized 1,4-Benzoxazine Derivatives

✍ Scribed by Martine Largeron; Anne Neudorffer; Marc Vuilhorgne; Estelle Blattes; Maurice-Bernard Fleury

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 112 KB
• Volume: 114
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/1521-3757(20020301)114:5<852::aid-ange852>3.0.co;2-b

✦ Synopsis

Quinonoid systems are powerful intermediates for organic synthesis and constitute potential precursors to numerous naturally occurring substances. However, the synthesis of quinonoid entities, particularly o-quinones and o-azaquinones, which are usually unstable and very prone to polymerization, is not highly developed. [2] The facile generation of oquinone-type structures by the electrochemical oxidation of related o-quinols and their well-known ability to react with nucleophiles [3] prompted us to investigate the reaction of highly reactive electrogenerated o-quinone species with amino alcohols, and we recently described the one-pot electrochemical synthesis of substituted 1,4-benzoxazine derivatives, a novel class of potent neuroprotective agents. [4] We also revealed a new mode of reactivity of these quinonoid systems, [5] in which electrogenerated 3,4-azaquinone 1 ox (Scheme 1) acts as an efficient catalyst for the Scheme 1. Mechanism of catalytic oxidation of primary aliphatic amines mediated by electrogenerated model quinonoid cofactor 1 ox .