Nickel-Catalyzed Synthesis of<i>N</i>-Aryl-1,2-dihydropyridines by [2+2+2] Cycloaddition of Imines with Alkynes through T-Shaped 14-Electron Aza-Nickelacycle Key Intermediates
作者:Yoichi Hoshimoto、Tomoya Ohata、Masato Ohashi、Sensuke Ogoshi
DOI:10.1002/chem.201304830
日期:2014.4.1
imines in nickel‐catalyzed [2+2+2] cycloaddition reactions with alkynes. In the presence of a nickel(0)/PCy3 catalyst, a reaction with N‐benzylidene‐P,P‐diphenylphosphinic amide was developed. Moreover, an application of N‐aryl imines to the reaction was also achieved by adopting N‐heterocyclic carbene ligands. The isolation of an (η2‐N‐aryl imine)nickel(0) complex containing a 14‐electron nickel(0) center
尽管有一种简单的方法可以合成1,2-二氢吡啶,但只有含N-磺酰基或吡啶基的亚胺才能实现亚胺与炔烃的过渡金属催化的[2 + 2 + 2]环加成反应。。考虑到1,2-二氢吡啶在制备各种有价值的有机分子中作为有用中间体的重要性,因此提供新颖的策略来扩大亚胺的范围将是非常值得的。本文中,我们报道了亚炔在镍催化的[2 + 2 + 2]环加成反应中成功扩大了亚胺的范围。在镍(0)/ PCY的存在3催化剂,与反应Ñ -benzylidene- P,P开发了二苯基次膦酰胺。此外,通过采用N-杂环卡宾配体,N-芳基亚胺也可用于该反应。的隔离(η 2 - ñ -芳基亚胺)镍(0)含有14电子镍(0)中心和一个T形14电子复合五元氮杂nickelacycle被示出。这些将被认为是反应的关键中间体。这些复合物的结构是通过NMR光谱学和X射线分析明确确定的。