Multifold Bond Cleavage and Formation between MeOH and Quinoxalines (or Benzothiazoles): Synthesis of Carbaldehyde Dimethyl Acetals

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• 作者：Yunkui Liu ; Bo Jiang ; Wei Zhang ; Zhenyuan Xu
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：February 1, 2013
• 年：2013
• 卷：78
• 期：3
• 页码：966-980
• 全文大小：778K
• 年卷期：v.78,no.3(February 1, 2013)
• ISSN：1520-6904

文摘

A K₂S₂O₈-mediated direct cross-coupling of quinoxalines (or benzothiazoles) with methanol leading to 2-quinoxalinyl (or 2-benzothiazolyl) carbaldehyde dimethyl acetals has been achieved. 2-Quinoxalinyl carbaldehyde dimethyl acetals were readily converted into 2-quinoxalinyl carbaldehydes in good to excellent yields under acidic conditions. Preliminary mechanistic studies suggest that the reaction proceeds via multifold bond cleavage and formation between methanol and N-heterocycles involving a dioxygen-participated radical process. This method allows for the synthesis of a variety of 2-quinoxalinyl (or 2-benzothiazolyl) carbaldehyde dimethyl acetals directly via cross-coupling of simple N-heterocyclic C鈥揌 bond and methanol under aldehyde-, acid-, and transition-metal-free conditions.