描述了用炔丙基醇进行的Ir(III)催化的苯甲酸氧化环化反应,以高度区域选择性的方式生成取代的异香豆素。该协议具有广泛的底物范围,具有较高的官能团耐受性。通过路易斯酸介导的环化作用将观察到的异香豆素转化为具有生物活性的四环茚并[ 2,1- c ]异香豆素。提出了一种可能的反应机理,并由详细的机理研究和DFT大力支持。
Rhodium(III)-Catalyzed C–H Olefination of Aromatic/Vinyl Acids with Unactivated Olefins at Room Temperature
作者:Subramanian Jambu、Masilamani Jeganmohan
DOI:10.1021/acs.orglett.0c01636
日期:2020.7.2
A Rh(III)-catalyzed COOH-assisted C–H alkenylation of aromaticacids with unactivated alkenes at room temperature is described. Further, the highly challenging β-C–H olefination of acrylic acids with unactivated olefins was also demonstrated. In these reactions, ortho-alkenylated aromatic/vinylic acids were prepared in good to excellent yields. A possible reaction mechanism involving ortho C–H activation
Ruthenium(II)-Catalyzed Cyclization of Aromatic Acids with Allylic Acetates via Redox-Free Two-Fold Aromatic/Allylic C–H Activations: Combined Experimental and DFT Studies
A Ru(II)-catalyzed, redox-free, two-fold aromatic/allylic C–H bond activation of aromatic acids with allylic acetates to give (Z)-3-ylidenephthalides is described. In the reaction, H2 was formed as a side product. The detailed mechanistic investigation and DFT studies including the transition-state analysis support the postulate that the C–H allylation takes place at the ortho position of aromatic
Palladium-Catalyzed H/D Exchange Reaction with 8-Aminoquinoline as the Directing Group: Access to ortho-Selective Deuterated Aromatic Acids and β-Selective Deuterated Aliphatic Acids
We develop a palladium-catalyzed H/D exchange reaction with 8-aminoquinoline as the directing group as well as D2O as the source of deuterium atom and solvent. This reaction achieves selectively H/D exchange at the ortho-C–H of aromatic amides and the β-C–H of aliphatic amide. Ortho-deuterated aromatic acids and β-deuterated aliphatic acids are obtained by removal of the directing group. And a possible
Well‐defined ruthenium(II) biscarboxylate complexes enabled selective ortho‐deuteration with weakly‐coordinating, synthetically useful carboxylic acid with outstanding levels of isotopiclabeling. The robust nature of the catalytic system was reflected by a broad functional group tolerance in an operationally‐simple manner, allowing the isotopelabeling of challenging pharmaceuticals and bioactive heterocyclic
Rh-catalyzed weak and traceless directing-group-assisted cascade C–H activation and annulation of sulfoxoniumylides with vinyl cyclopropanes as a coupling partner have been accomplished to furnish functionalized cyclopropane-fused tetralones at moderate temperature. The C–C bond formation, cyclopropanation, functional group tolerance, late-stage diversifications of drug molecules, and scale-up are