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
Direct, Catalytic, and Regioselective Synthesis of 2-Alkyl-, Aryl-, and Alkenyl-Substituted <i>N</i>-Heterocycles from <i>N</i>-Oxides
作者:Oleg V. Larionov、David Stephens、Adelphe Mfuh、Gabriel Chavez
DOI:10.1021/ol403631k
日期:2014.2.7
A one-step transformation of heterocyclic N-oxides to 2-alkyl-, aryl-, and alkenyl-substituted N-heterocycles is described. The success of this broad-scope methodology hinges on the combination of copper catalysis and activation by lithium fluoride or magnesium chloride. The utility of this method for the late-stage modification of complex N-heterocycles is exemplified by facile syntheses of new structural
Copper-catalyzed direct C–H arylation of pyridineN-oxides with arylboronic esters for the one-pot synthesis of 2-arylpyridines without an additional reductant.