State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, PR China.
University of Chinese Academy of Sciences, Beijing, 100049, PR China.
Nat Commun. 2020 Jun 19;11(1):3113. doi: 10.1038/s41467-020-16948-5.
Amides are versatile synthetic building blocks and their selective transformations into highly valuable functionalities are much desirable in the chemical world. However, the diverse structure and generally high stability of amides make their selective transformations challenging. Here we disclose a chemodivergent transformation of primary, secondary and tertiary amides by using 1,1-diborylalkanes as pro-nucleophiles. In general, selective B-O elimination occurs for primary, secondary amides and tertiary lactams to generate enamine intermediate, while tertiary amides undergo B-N elimination to generate enolate intermediate. Various in situ electrophilic trapping of those intermediates allows the chemoselective synthesis of α-functionalized ketones, β-aminoketones, enamides, β-ketoamides, γ-aminoketones, and cyclic amines from primary, secondary, tertiary amides and lactams. The key for these transformations is the enolization effect after the addition of α-boryl carbanion to amides.
酰胺是多功能的合成砌块，其将选择性转化为高价值的功能基团在化学界是非常需要的。然而，酰胺结构的多样性和通常较高的稳定性使得它们的选择性转化具有挑战性。在这里，我们披露了使用 1,1-二硼烷作为亲核试剂对伯、仲和叔酰胺进行化学发散转化。一般来说，伯、仲酰胺和叔内酰胺选择性地发生 B-O 消除，生成烯胺中间体，而叔酰胺发生 B-N 消除，生成烯醇化物中间体。这些中间体的各种原位亲电捕获允许从伯、仲、叔酰胺和内酰胺中选择性合成 α-官能化酮、β-氨基酮、烯酰胺、β-酮酰胺、γ-氨基酮和环状胺。这些转化的关键是α-硼碳负离子加成到酰胺后发生烯醇化效应。
