Silver‐Promoted Fluorination Reactions of α‐Bromoamides
Silver‐Promoted Fluorination Reactions of α‐Bromoamides
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银促进的 α-溴酰胺氟化反应
DOI：
10.1002/chem.202004769
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Ishikawa Takeshi
中科院分区：
文献类型：
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作者：
Mizuta Satoshi;Kitamura Kanami;Kitagawa Ayako;Yamaguchi Tomoko;Ishikawa Takeshi
本文报道了在温和的条件下，银促进的−-溴酰胺中C-α-F键的形成。这种简单的方法使得能够获得涉及生物分子支架的叔烷基氟化物、仲烷基氟化物和伯烷基氟化物。这种转化适用于伯胺和仲酰胺，并表现出广泛的官能团耐受性。动力学实验表明，反应速率按3°>；2°>；1°α-碳原子的顺序增加。此外，还发现酸性酰胺质子在加速反应中起着重要的作用。机械学研究表明生成了氮杂环酮中间体，该中间体经过随后的亲核加成形成具有立体专一性的C−F键(即，保持构型)。还展示了用AgI合成空间位阻的醇和醚。列举了α-溴代酰胺与O亲核试剂的反应实例。
Silver‐promoted C−F bond formation in α‐bromoamides by using AgF under mild conditions is reported. This simple method enables access to tertiary, secondary, and primary alkyl fluorides involving biomolecular scaffolds. This transformation is applicable to primary and secondary amides and shows broad functional‐group tolerance. Kinetics experiments revealed that the reaction rate increased in the order of 3°>2°>1° α‐carbon atom. In addition, it was found that the acidic amide proton plays an important role in accelerating the reaction. Mechanistic studies suggested generation of an aziridinone intermediate that undergoes subsequent nucleophilic addition to form the C−F bond with stereospecificity (i.e., retention of configuration). The synthesis of sterically hindered alcohols and ethers by using AgIis also demonstrated. Examples of reactions of α‐bromoamides with O nucleophiles are presented.