Synthesis of vicinally functionalized 1,4-dihydropyridines and diazabicycles via a pseudo-intramolecular process
作者:Nagatoshi Nishiwaki、Shotaro Hirao、Jun Sawayama、Haruyasu Asahara、Ryuichi Sugimoto、Kazuya Kobiro、Kazuhiko Saigo
DOI:10.1016/j.tet.2013.11.044
日期:2014.1
An alpha-nitro-delta-keto nitrile readily forms the corresponding ammonium salt immediately upon treatment with an amine. When the amine liberated under equilibrium, the nucleophilic amine and the electrophilic keto nitrile come close to each other to afford so-called an intimate pair. The spatial proximity realized an efficient reaction to give a 2-amino-3-nitro-1,4-dihydropyridine; the reaction proceeded like an intramolecular reaction although it is actually an intermolecular reaction, namely the pseudo-intramolecular reaction. The bifunctionality of the keto nitrile also enabled the pseudo-intramolecular imination followed by tandem cyclization leading to diazabicyclic frameworks. (C) 2013 Elsevier Ltd. All rights reserved.