4-HO-TEMPO-Catalyzed Redox Annulation of Cyclopropanols with Oxime Acetates toward Pyridine Derivatives
作者:Jun-Long Zhan、Meng-Wei Wu、Dian Wei、Bang-Yi Wei、Yu Jiang、Wei Yu、Bing Han
DOI:10.1021/acscatal.9b00832
日期:2019.5.3
for the synthesis of pyridines through the annulation of cyclopropanols and oxime acetates has been developed. This protocol features good functional group tolerance and high chemoselectivity and also promises to be efficient for the late-stage functionalization of skeletons of drugs and natural products. Mechanism studies indicate that the reaction involves the in situ generated α,β-unsaturated ketones
C<sub>6</sub>
-Selective Direct Arylation of 2-Phenylpyridine <i>via</i>
an Activated <i>N</i>
-methylpyridinium Salt: A Combined Experimental and Theoretical Study
incorporation studies revealed that the C−Hbond acidity is improved significantly in N‐methylpyridinium salts compared with their N‐Oxide and N‐iminopyridinium ylide counterparts, thus solving the long‐standing problem associated with previous strategies for the synthesis of diaryl pyridines. Finally, the control experiments and DFT calculations supported a Pd‐catalyzed and Cu‐mediated mechanism in
Phosphine Ligand‐Free Ruthenium Complexes as Efficient Catalysts for the Synthesis of Quinolines and Pyridines by Acceptorless Dehydrogenative Coupling Reactions
作者:Bin Guo、Tian‐Qi Yu、Hong‐Xi Li、Shi‐Qi Zhang、Pierre Braunstein、David J. Young、Hai‐Yan Li、Jian‐Ping Lang
DOI:10.1002/cctc.201900435
日期:2019.5.20
corresponding ligand in EtOH. Five Ru(II) complexes [LRu(DMSO‐κS)Cl2] (2 a: L=L1; 2 b: L=L2; 2 c: L=L3; 2 d: L=L4; 2bMe: L=L2Me) were formed by reducing the corresponding Ru(III) complex in refluxing EtOH. The latter complexes could also be prepared directly by refluxing Ru(DMSO)4Cl2 with the corresponding ligand in EtOH. These Ru(III) and Ru(II) complexes, especially 1 b/2 b, exhibited high catalytic
Direct synthesis of ring-fused quinolines and pyridines catalyzed by <i>NN</i><sub><i>H</i></sub><i>Y</i>-ligated manganese complexes (Y = NR<sub>2</sub> or SR)
作者:Zheng Wang、Qing Lin、Ning Ma、Song Liu、Mingyang Han、Xiuli Yan、Qingbin Liu、Gregory A. Solan、Wen-Hua Sun
DOI:10.1039/d1cy01945g
日期:——
Four cationic manganese(I) complexes, [(fac-NNHN)Mn(CO)3]Br (Mn-1–Mn-3) and [(fac-NNHS)Mn(CO)3]Br (Mn-4) (where NNH is a 5,6,7,8-tetrahydro-8-quinolinamine moiety), have been synthesized and evaluated as catalysts for the direct synthesis of quinolines and pyridines by the reaction of a γ-amino alcohol with a ketone or secondary alcohol; NNHS-ligated Mn-4 proved the most effective of the four catalysts
四种阳离子锰( I )配合物,[( fac-NN H N )Mn(CO) 3 ]Br ( Mn-1 – Mn-3 ) 和 [( fac-NN H S )Mn(CO) 3 ]Br ( Mn -4 )(其中N H是 5,6,7,8-四氢-8-喹啉胺部分),已被合成并评估为通过 γ-氨基醇与酮或仲醇;NN H S -连接的Mn-4被证明是四种催化剂中最有效的。在催化剂负载量为 0.5-5.0 mol% 的情况下,反应进行得很好,并且可以耐受不同的官能团,如烷基、环烷基、烷氧基、氯化物和杂芳基。基于 DFT 计算和实验证据,提出了一种涉及无受体脱氢偶联 (ADC) 的机制。值得注意的是,这种基于锰的催化方案为广泛合成重要的取代单环、双环和三环N-杂环(包括 50 个喹啉和 26 个吡啶实例)提供了一条有前途的绿色环保途径,分离产率高达 93 %。
Highly Regioselective Assembly of Di- or Trisubstituted Pyridines from Arynes, Isocyanides, and 3-Bromo- or 3-Acetoxypropynes
作者:Feng Sha、Hui Shen、Xin-Yan Wu
DOI:10.1002/ejoc.201300001
日期:2013.5
synthetic method for the preparation of di- and trisubstitutedpyridines with high regioselectivity through an intramolecular pericyclization strategy is disclosed. The multicomponent reaction of isocyanides, arynes, and 3-bromopropyne affords disubstituted pyridines in good yields. In contrast, the use of 3-acetoxypropyne results in the formation of trisubstitutedpyridines through intramolecular pericyclization