An Alkylidene Carbene C–H Activation Approach toward the Enantioselective Syntheses of Spirolactams: Application to the Synthesis of (−)-Adalinine
作者:Krishna Annadi、Andrew G. H. Wee
DOI:10.1021/acs.joc.5b02582
日期:2016.2.5
that the reaction efficiency is sensitive to the reaction temperature and the amount of lithio(trimethylsilyl)diazomethane employed, which led to the development of optimal reaction conditions for effecting alkylidene carbene generation-C–H insertion. Using the optimal reaction conditions, good to high yields (53–76%) of both γ- and δ-lactam spirocycles were obtained. The synthetic utility of the spirolactams
一种基于原位的方法开发了5-(3-氧代丁基)吡咯烷-2-酮和6-(3-氧代丁基)哌啶-2-酮的亚烷基卡宾生成-CH插入反应,用于1-氮杂螺的对映选择性合成[4,4]非6-烯-2-酮和6-氮杂螺[4,5] dec-1-烯-7-酮。所需的5-(3-氧丁基)吡咯烷酮-2-酮和6-(3-氧丁基)哌啶-2-酮是由以5-(丁-2-烯基)吡咯烷酮-2为代表的内部烯烃的Wacker氧化制得的-1和6-(but-2-enyl)piperidin-2-ones。Wacker氧化具有出色的区域选择性(≥92:8),并能获得高收率(78–89%)的所需内酰胺酮。对Wacker氧化的进一步研究结果表明,这些内酰胺烯烃中氧化的高区域选择性可能是由于内酰胺氮在反应过程中通过与Pd(II)的分子内配位作用而参与的。对内酰胺酮的亚烷基卡宾生成-CH插入反应的研究表明,反应效率对反应温度和所使用的硫代(三甲基甲硅烷基)重氮甲