Palladium-Catalyzed meta-C–H Olefination of Arene-Tethered Diols Directed by Well-Designed Pyrimidine-Based Group
摘要:
The palladium-catalyzed meta-olefination of arene-tethered diols attached to a well-designed pyrimidine moiety is presented. Applications of the protocol are illustrated by the synthesis of various diol-based natural products, such as coumarins, phenylpropanoids, stilbenes, and chalcones. Advantages of this method are demonstrated through the easy removal of the template and a gram-scale olefination reaction. Finally, experimental verification, including H-1 NMR, ESI-MS and IR, and DFT studies are undertaken to elucidate the mechanistic complexity.
Palladium-Catalyzed meta-C–H Olefination of Arene-Tethered Diols Directed by Well-Designed Pyrimidine-Based Group
摘要:
The palladium-catalyzed meta-olefination of arene-tethered diols attached to a well-designed pyrimidine moiety is presented. Applications of the protocol are illustrated by the synthesis of various diol-based natural products, such as coumarins, phenylpropanoids, stilbenes, and chalcones. Advantages of this method are demonstrated through the easy removal of the template and a gram-scale olefination reaction. Finally, experimental verification, including H-1 NMR, ESI-MS and IR, and DFT studies are undertaken to elucidate the mechanistic complexity.
A simple catalytic method involving all‐metal aromatic frameworks as precatalysts ensures an efficient route to (Z)‐alkenes. Aromatic triangular palladium clusters were used to reduce internalalkynes without any trace of the formation of alkane side products. These trinuclear complexes provide a catalytic system that parallels the activity and selectivity of their best mononuclear peers, and the catalyst
Functionalized Arylzinc Compounds in Ethereal Solvent: Direct Synthesis from Aryl Iodides and Zinc Powder and Application to Pd-Catalyzed Reaction with Allylic Halides
Arylzinc compounds, ArZnX, were conveniently prepared in high yields by the reaction of zincpowder with aryl iodides, which contain electron-withdrawing groups such as CO(2)CH(3), CN, Br, or CF(3) at the ortho-, meta- or para-position, or electron-donating groups such as CH(3), OCH(3), or H, at 70 degrees C in THF, at 100 degrees C, or at 130 degrees C in diglyme, respectively. Pd(dba)(2) exhibited
Copper-Mediated Trifluoromethylation–Allylation of Arynes
作者:Xinkan Yang、Gavin Chit Tsui
DOI:10.1021/acs.orglett.8b00101
日期:2018.2.16
An unprecedented three-component copper-mediated vicinal trifluoromethylation–allylation of arynes is described. A wide range of structurally diverse trifluoromethylated allylarenes can be quickly assembled in one step. The application of the method has been demonstrated in the expedient synthesis of the CF3-containing analogue of the antispasmodic drug papaverine. The new reactivity of the [CuCF3]
The first electrophilic Pd(II)-catalyzed allylic C H alkylation is reported, providing a novel method for formation of sp3-sp3 C C bonds directly from C H bonds. A wide range of aromatic and heteroaromatic linear (E)-alpha-nitro-arylpentenoates are obtained as single olefin isomers in excellent yields directly from terminal olefin substrates and methyl nitroacetate. The use of DMSO as a pi-acidic ligand
A Transition-Metal-Free Synthesis of Fluorinated Naphthols
作者:Jeffrey M. Hammann、Teresa A. Unzner、Thomas Magauer
DOI:10.1002/chem.201402098
日期:2014.5.26
electrocyclization, followed by rearomatization. This concept enables the rapid conversion (three steps) of various commercially available 3‐(trifluoromethyl)phenols into novel fluorine‐containing naphthols, which are difficult to prepare by previous methods. The reported sequence was also extended to a one‐pot transformation of 3‐(trifluoromethyl)phenols into 5‐fluoronaphthalen‐1‐ols.