为环外β-烯胺酮的分子内环化一个高效和灵活的协议已经公开了carbazolones和咪唑并[1,2的合成一个]吡啶通过高价碘促进的抗衡阴离子控制自由基机理(III) 。HTIB和AgSbF 6的协同行为在通过CC和CN键形成所需的分子内环化过程中起着至关重要的作用。机械学的见解表明,系统中涉及的两个竞争性反应是由抗衡阴离子的性质决定的,抗衡阴离子的性质决定了最终产物的形成。制备并分离了各种咔唑酮和咪唑并[1,2- a ]吡啶分子,收率良好至极佳。
Synthesis of fused-tetrahydropyrimidines: one-pot methylenation–cyclization utilizing two molecules of CO<sub>2</sub>
作者:Yulei Zhao、Xuqiang Guo、Yulan Du、Xinrui Shi、Shina Yan、Yunlin Liu、Jinmao You
DOI:10.1039/d0ob01504k
日期:——
A methylenation–cyclization reaction, employing cyclic enaminones with primary aromatic amines and two molecules of CO2, furnishing fused-tetrahydropyrimidines, is discussed. In this Cs2CO3 and ZnI2 catalyzed one-pot two-step procedure, two molecules of CO2 were selectively converted to methylene groups. The multi-component reaction might proceed through the formation of bis(silyl)acetal which was
讨论了使用环状烯胺酮与伯芳香胺和两个 CO 2分子,提供稠合四氢嘧啶的亚甲基化-环化反应。在这个Cs 2 CO 3和ZnI 2催化的一锅两步法中,两个CO 2分子被选择性地转化为亚甲基。多组分反应可能通过形成双(甲硅烷基)缩醛进行,然后是缩合和进一步的氮杂-狄尔斯-阿尔德反应。氢喹唑啉、氢环戊二烯[ d ]嘧啶和氢茚并[1,2- d ]嘧啶衍生物可以以CO 2作为C1源有效地制备。
Mechanism of Hydrolysis and Structure–Stability Relationship of Enaminones as Potential Prodrugs of Model Primary Amines
作者:Vijay H. Naringrekar、Valentino J. Stella
DOI:10.1002/jps.2600790213
日期:1990.2
compound, suggesting that the rate-controlling step in the hydrolysis of the enaminones was the proton addition to the vinyl carbon of the enaminone. Enaminones formed with cyclic 1,3-dicarbonyl compounds were significantly more stable than those formed with structurally similar acyclic compounds. Based on chemical stability considerations alone, enaminones do not appear to be good candidates as prodrugs of
among a range of catalytically relevant enamines. Spin population analysis disclosed that enamine radical cations mainly exhibit the carbon-center free radical feature. Taking experimental and computation data together, a comprehensive picture about the redox property of enamines is presented, which would provide guidance in the development of oxidative enamine catalysis and transformations.
A variety of N-substituted 3-aminocyclohex-2-enones were converted into the corresponding N-arylated α-iodo enaminones in high yields via concurrent α-iodination and N-arylation mediated by ArI(OAc)2. A mechanism is postulated to account for the reaction differences between the cyclic and the acyclic β-enaminones, which undergo predominant α-acetoxylation under the same reaction conditions.
A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd2(dba)3-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique