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论文类型：期刊论文

发表时间：2016-11-21

发表刊物：CHEMISTRY-A EUROPEAN JOURNAL

收录刊物：SCIE、EI、PubMed

卷号：22

期号：48

页面范围：17156-17159

ISSN号：0947-6539

关键字：amino acids; carbon dioxide fixation; carboxylation; transition-metal-free synthesis; umpolung

摘要：A straightforward and transition-metal-free approach for the efficient synthesis of -arylglycine derivatives from aromatic imines and carbon dioxide was enabled by an umpolung carboxylation reaction. Various substituted diphenylmethimines underwent the carboxylation smoothly with carbon dioxide in the presence of potassium tert-butoxide and 18-crown-6 to give the corresponding carboxylated products in good to high yields. Besides the enhancement of the solubility of potassium tert-butoxide in THF, 18-crown-6 also plays key roles in suppressing the reverse protonation or 1, 3-proton shift isomerization as well as by stabilizing the carboxylated intermediate.