Directed C–H Functionalization Reactions with a Picolinamide Directing Group: Ni-Catalyzed Cleavage and Byproduct Recycling
作者:Sovan Biswas、Narendraprasad Reddy Bheemireddy、Mathias Bal、Ben F. Van Steijvoort、Bert U. W. Maes
DOI:10.1021/acs.joc.9b02299
日期:2019.10.18
first Boc activated into tertiary N-Boc-N-substituted picolinamides. These were then cleaved via a Ni-catalyzed esterification reaction with EtOH to give valuable N-Boc protected amines. Ni(cod)2 was used as a catalyst without any ligands or base additives. The byproduct, ethyl 2-picolinate can be used to install the picolinamide DG in a direct or indirect manner on amines. The protocol exhibits a
已经开发了一种有效的策略,用于裂解吡啶甲酸酰胺引导基团(DG)和回收所产生的副产物。在该方案中,首先将Picolinamides进行Boc活化,形成叔N-Boc-N-取代的picolinamides。然后将它们通过与EtOH的Ni催化酯化反应裂解,得到有价值的N-Boc保护的胺。Ni(cod)2被用作没有任何配体或碱添加剂的催化剂。副产物2-吡啶甲酸乙酯可用于直接或间接将吡啶甲酸酰胺DG安装在胺上。该方案显示出宽泛的官能团耐受性和高产率。为了证明这种方法的实用性,将其应用到了以2-吡啶甲酸酰胺为DG的CH官能化文献的最新选择中。