A straightforward method for the synthesis of highlyfunctionalizedvinylarenes through palladium‐catalyzed, norbornene‐mediated CHactivation/carbene migratory insertion is described. Extension to a one‐pot procedure is also developed. Furthermore, this method can also be used to generate polysubstituted bicyclic molecules. The reaction proceeds under mild conditions to give the products in satisfactory
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
situ from tosylhydrazones. In addition, by using chiral dirhodium catalysts, we also achieved an asymmetric version of the reaction with good to excellent enantioselectivities (up to 98:2 e.r.). This is the first enantioselective heteroatom-hydrogen bond insertion reaction to use unstabilized diazo compounds as carbene precursors. The protocol exhibited good functional group tolerance and could be carried
A palladium-catalyzed heck-type cascadecyclization of (Z)-1-iodo-1,6-dienes with N-tosyl hydrazones is reported. The alkylpalladium intermediate coupled with the diazo compound, generating the second alkylpalladium species bearing two β-H, which generated a terminal alkene as the major products in the anti-Zaitsev way via the highly regioselective β-H elimination. It provided a new way to synthesize
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。