approach for the synthesis of polysubstituted pyridines has been achieved through copper-catalyzed oxidative sp3 C–H coupling of oxime acetates with toluene derivatives. Besides, benzylamine and p-toluenesulfonylhydrazone were also introduced to react with oxime acetates to enrich the diversity of this synthetic method. These transformations provide highly flexible and facile preparation of substituted pyridines
Copper-catalyzed coupling of oxime acetates with aldehydes offers a new strategy for the synthesis of highly substituted pyridines. This novel method tolerates a wide range of functionality and allows for rapid elaboration of the oxime acetates into a variety of substituted pyridines.
TMSOTf-mediated Kröhnke pyridine synthesis using HMDS as the nitrogen source under microwave irradiation
作者:Chieh-Kai Chan、Yi-Hsiu Chung、Cheng-Chung Wang
DOI:10.1039/d2ra00084a
日期:——
An efficient protocol for the preparation of pyridine skeletons has been successfully developed involving the TMSOTf/HMDS (trifluoromethanesulfonic acid/hexamethyldisilane) system for the intermolecular cyclization of chalcones under MW (microwave) irradiation conditions. This method provides a facile approach to synthesize 2,4,6-triaryl or 3-benzyl-2,4,6-triarylpyridines in good to excellent yields
A highly efficient one‐pot synthesis of polysubstituted pyridine has been achieved through copper‐catalyzed oxidative sp3 C−H coupling of acetophenones with toluene derivatives. Besides, the polysubstituted benzene was obtained through copper‐catalyzed coupling of acetophenones. Both of the reactions exhibited a good functional group tolerance to produce a 2,4,6‐triphenylpyridine or 1,3,5‐triarylbenzene
Synthesis of Kröhnke pyridines through iron-catalyzed oxidative condensation/double alkynylation/amination cascade strategy
作者:Kovuru Gopalaiah、Renu Choudhary
DOI:10.1016/j.tet.2021.132429
日期:2021.10
protocol for the synthesis of symmetrical and unsymmetrical 2,4,6-trisubstituted pyridines via oxidative cascade annulation of arylacetylenes with benzylamines has been developed. The reaction proceeds smoothly utilizing iron(II) triflate as a catalyst and molecular oxygen as an oxidant with broad substrate scope. Mechanistic studies reveal that the reaction may be experiences an oxidative condensation