Strain-Release-Driven Homologation of Boronic Esters: Application to the Modular Synthesis of Azetidines
作者:Alexander Fawcett、Amna Murtaza、Charlotte H. U. Gregson、Varinder K. Aggarwal
DOI:10.1021/jacs.9b01513
日期:2019.3.20
boronate complex which, upon N-protonation with acetic acid, undergoes 1,2-migration with cleavage of the central C-N bond to relieve ring strain. The methodology is applicable to primary, secondary, tertiary, aryl, and alkenyl boronic esters and occurs with complete stereospecificity. The homologated azetidinyl boronic esters can be further functionalized through reaction of the N-H azetidine, and through
氮杂环丁烷是药物化学中的重要基序,但其合成方法数量有限。在此,我们通过利用与氮杂双环[1.1.0]丁烷相关的高环应变,提出了一种模块化构造的新方法。生成氮杂双环[1.1.0]丁基锂,然后用硼酸酯捕获它,得到中间体硼酸盐络合物,在用乙酸进行 N-质子化后,会发生 1,2-迁移,中心 CN 键断裂以减轻环应变. 该方法适用于伯、仲、叔、芳基和烯基硼酸酯,并具有完全的立体专一性。同系化氮杂环丁烷基硼酸酯可以通过NH氮杂环丁烷的反应和通过硼酸酯的转化而进一步官能化。该方法被应用于一个简短的,