Nucleophilic Reaction upon Electron-Deficient Pyridone Derivatives. X.One-Pot Synthesis of 3-Nitropyridines by Ring Transformation of 1-Methyl-3,5-dinitro-2-pyridone with Ketones or Aldehydes in the Presence of Ammonia
作者:Yasuo Tohda、Miyuki Eiraku、Takao Nakagawa、Yumi Usami、Masahiro Ariga、Toshihide Kawashima、Keita Tani、Hiroko Watanabe、Yutaka Mori
DOI:10.1246/bcsj.63.2820
日期:1990.10
The reaction of 1-methyl-3,5-dinitro-2-pyridone (1a) with ketones or aldehydes in the presence of ammonia gave alkyl- and/or aryl-substituted 3-nitropyridines (6) in moderate to high yields. Enamines derived from the ketones gave better results than did the ketones themselves; on the other hand, those derived from the aldehydes gave no 6 at all. On the basis of deuterium-labeled experiments, a mechanism comprising competitive ring transformations of 1a is proposed.
Nucleophilic Dearomatization of Pyridines under Enamine Catalysis: Regio-, Diastereo-, and Enantioselective Addition of Aldehydes to Activated <i>N</i>-Alkylpyridinium Salts
enamines to azinium salts is a powerful tool for the synthesis of enantioenriched heterocycles. An unprecedented asymmetric dearomative addition of aldehydes to activated N-alkylpyridinium salts is presented. The process exhibits complete C-4 regioselectivity along with high levels of diastereo- and enantiocontrol, achieving a high-yieldingsynthesis of a broad range of optically active 1,4-dihydropyridines
将手性烯胺催化加成至叠氮盐是合成对映体富集的杂环的有力工具。提出了空前的不对称的将醛向活化的N-烷基吡啶鎓盐中脱醛的方法。该方法具有完全的C-4区域选择性以及高水平的非对映和对映控制,可实现多种旋光1,4-二氢吡啶的高产率合成。此外,提出的方法能够合成功能化的八氢吡咯并[2,3- c ]吡啶,这是抗癌肽模拟物的核心结构。