Synthesis of Multifunctionalized 1,2,3,4-Tetrahydropyridines, 2,3-Dihydropyridin-4(1H)-ones, and Pyridines from Tandem Reactions Initiated by [5+1] Cycloaddition of N-Formylmethyl-Substituted Enamides to Isocyanides: Mechanistic Insight and Synthetic Appl
作者:Chuan-Hu Lei、De-Xian Wang、Liang Zhao、Jieping Zhu、Mei-Xiang Wang
DOI:10.1002/chem.201303221
日期:2013.12.9
trans‐3‐hydroxy‐4‐arylamino‐ or ‐alkylamino‐1,2,3,4‐tetrahydropyridines, whereas acylation of the imino group followed by acidic hydrolysis produced 1,6‐disubstituted 3‐acyloxy‐2,3‐dihydropyridin‐4(1H)‐ones. Aerobic oxidation led to the aromatization followed by intermolecular acyl‐group transfer from the pyridinium nitrogen to the 3‐hydroxy moiety, thereby yielding substituted 3‐acyloxy‐4‐aminopyridines. Synthetic
串联反应可有效合成多功能的1,2,3,4-四氢吡啶,2,3-二氢吡啶-4(1 H)-酮和吡啶衍生物,并研究了反应机理。合成级联反应是由N-甲酰基甲基取代的叔酰胺经Zn(OTf)2介导的[5 + 1]环加成反应成异氰酸酯的,因此导致了多功能的杂环烯胺亚胺中间体。通过用Me 4 NBH(OAc)3非对映选择性还原亚胺官能团来拦截中间体,得到1,6-二取代的反式-3-羟基-4-芳基氨基或烷基氨基1,2,3,4-四氢吡啶,而亚氨基的酰化再进行酸性水解则产生1,6-二取代的3-酰氧基-2,3-二氢吡啶4( 1 H)-个。有氧氧化导致芳构化,随后分子内的酰基基团从吡啶鎓氮转移到3-羟基部分,从而产生取代的3-酰氧基-4-氨基吡啶。顺式,顺式-4,5--4-二羟基-2-苯基哌啶和反式,反式-4-氨基-5-羟基-2-苯基哌啶化合物的便捷,立体选择性合成证明了所得产物的合成潜力,这很重要。在药物化学中,通过简单而实用的还原反应。