College of Chemistry, Beijing Normal University, Beijing 100875, China.
Org Biomol Chem. 2012 May 28;10(20):4088-94. doi: 10.1039/c2ob25137j. Epub 2012 Apr 13.
The NHC-catalyzed reactions of ortho electron-deficient vinyl substituted arylaldehydes with nitrosoarenes were studied. The reactions produced multifunctional 2,3-benzoxazin-4-ones in good to excellent yields via a cascade aza-benzoin reaction between aldehyde and nitroso groups followed by an intramolecular oxo-Michael addition. The resulting 1-acetate substituted 2,3-benzoxazinones were transformed into a new type of β-hydroxycarboxylate derivatives or 3-oxo-1-isobenzofuranacetates, respectively, under different reductive conditions. This work not only provides a simple and efficient method for the construction of multifunctional 2,3-benzoxazin-4-ones of potential pharmacological interest, but also expands the application of NHC-catalyzed cascade reactions in the formation of carbon-heteroatom and heteroatom-heteroatom bonds.
研究了 NHC 催化的邻位缺电子乙烯取代芳基醛与亚硝基芳烃的反应。该反应通过醛和亚硝基之间的级联氮杂苯并二氢吡喃酮反应，然后进行分子内氧代迈克尔加成，以良好至优秀的收率生成多功能 2,3-苯并恶嗪-4-酮。在不同的还原条件下，得到的 1-乙酸酯取代的 2,3-苯并恶嗪酮分别转化为新型β-羟基羧酸酯衍生物或 3-氧代-1-异苯并呋喃乙酸酯。这项工作不仅为构建具有潜在药理意义的多功能 2,3-苯并恶嗪-4-酮提供了一种简单有效的方法，而且还扩展了 NHC 催化的级联反应在形成碳-杂原子和杂原子-杂原子键中的应用。
