Pd-Catalyzed Highly Regio- and Stereoselective Formation of C–C Double Bonds: An Efficient Method for the Synthesis of Benzofuran-, Dihydrobenzofuran-, and Indoline-Containing Alkenes
A highly regio- and stereoselective C–C double bond formation reactionvia Pd-catalyzed Heck-type cascade process with N-tosylhydrazones has been developed. Various N-tosylhydrazones derived from both ketones and aldehydes are found to be efficient substrates to provide di- and trisubstitutedolefins with high regio- and stereoselectivity. Furthermore, this reaction has a good functional group tolerance
Copper(<scp>i</scp>)-catalyzed benzylation of triazolopyridine through direct C–H functionalization
作者:Madhava Reddy Lonka、Jinquan Zhang、Thirupathi Gogula、Hongbin Zou
DOI:10.1039/c9ob01433k
日期:——
A general and efficient copper-catalyzed benzylation reaction of triazolopyridine with N-tosylhydrazones was developed. This reaction forms a C(sp2)-C(sp3) bond through cross-coupling, and represents an exceedingly practical method to afford 3-benzylated triazolopyridines in moderate to good yields. A proposed mechanistic pathway underlying this reaction was outlined. This catalytic transformation
Directed C–C bond cleavage of a cyclopropane intermediate generated from<i>N</i>-tosylhydrazones and stable enaminones: expedient synthesis of functionalized 1,4-ketoaldehydes
-quaternary centers via regioseletive C-C bond activation has been described. Through cyclopropanation of bench-stable enaminones with in situ generated diazo reagents from N-tosylhydrazones, followed by selective C-C bond cleavage of the cyclopropane ring affords the 1, 4-ketoaldehyde derivatives in good to excellent yields. This method works with broad substrate scope and high regioseletivity.
Selective construction of 2-substituted benzothiazoles from o-iodoaniline derivatives S8 and N-tosylhydrazone via a copper-promoted [3 + 1 + 1]-type cyclization reaction has been realized. In the protocol, the carbon atom on N-tosylhydrazone could be regulated to construct benzothiazole by changing the reaction system. Furthermore, the transformation has achieved the construction of multiple carbon-heteroatom
Pd-Catalyzed Coupling of Thioamides with <i>N</i>-Tosylhydrazones/Trapping by Esters Cascade Reaction
作者:Zhongliang Cai、Zhi Yao、Liqin Jiang
DOI:10.1021/acs.orglett.0c03796
日期:2021.1.15
N,N-Disubstituted thioamides coupled with N-tosylhydrazones under Pd(TFA)2/tBuXPhos catalyst and NaOtBu, and the intermediates from palladium carbene migratory insertion containing β-hydrogen were trapped by intramolecular esters activated by BF3·Et2O instead of undergoing β-H elimination, providing polyfunctional thiophen-3(2H)-ones with sulfur-containing tetrasubstituted carbon centers in moderate
在Pd(TFA)2 / t BuXPhos催化剂和NaO t Bu催化下,N,N-二取代硫代酰胺与N-甲苯磺酰coupled偶合,以及含β-氢的钯卡宾迁移插入的中间体被BF 3 ·Et 2活化的分子内酯捕获。O代替β- H消除,提供多官能噻吩-3(2H含硫四取代碳原子的α-酮,产率中等至良好。该反应具有一次操作即可形成三个键,无味,安全且易于获得的底物,广泛的底物范围和出色的官能团耐受性的特点。