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
Copper-catalyzed direct C–H arylation of pyridineN-oxides with arylboronic esters for the one-pot synthesis of 2-arylpyridines without an additional reductant.
Modular Pyridine Synthesis from Oximes and Enals through Synergistic Copper/Iminium Catalysis
作者:Ye Wei、Naohiko Yoshikai
DOI:10.1021/ja312346s
日期:2013.3.13
ketoximes and α,β-unsaturated aldehydes that is synergistically catalyzed by a copper(I) salt and a secondary ammonium salt (or amine). This redox-neutral reaction allows modular synthesis of a variety of substituted pyridines under mild conditions with tolerance of a broad range of functional groups. The reaction is driven by a merger of iminium catalysis and redox activity of the copper catalyst, which
我们在此描述了由铜(I)盐和仲铵盐(或胺)协同催化的 O-乙酰基酮肟和 α,β-不饱和醛的 [3+3] 型缩合反应。这种氧化还原中性反应允许在温和条件下模块化合成各种取代的吡啶,并具有广泛的官能团耐受性。该反应由亚胺催化和铜催化剂的氧化还原活性的结合驱动,最初会还原肟 NO 键以生成亲核铜 (II) 烯酰胺,然后将二氢吡啶中间体氧化为吡啶产物。