Recyclable heterogeneous gold(I)-catalyzed oxidation of internal acylalkynes: Practical access to vicinal tricarbonyls
作者:Wenli Hu、Bin Huang、Bingbo Niu、Mingzhong Cai
DOI:10.1016/j.tetlet.2021.152953
日期:2021.3
A highly efficient heterogeneous gold(I)-catalyzed oxidation of internal acylalkynes has been developed using 2,6-dichloropyridine N-oxide as the oxidant in dichloromethane (CH2Cl2) at room temperature, providing a novel and practical approach for the construction of diverse vicinal tricarbonyls such as α,β-diketoesters, 1,2,3-triketones, and α,β-diketoamides in good to excellent yields. The heterogeneous
Synthesis of 2-Amino-6-phenyl-4<i>H</i>-pyran-4-ones
作者:Joel Morris、Donn G. Wishka
DOI:10.1055/s-1994-25402
日期:——
The treatment of a series of phenylacetylenic ß-keto amides with methanesulfonic acid produces a high yielding intramolecular cyclization to the corresponding 2-amino-6-phenyl-4H-pyran-4-ones.
Catalytic enantioselective access to disubstituted functionalized gem‐difluorocyclopropanes, which are emerging fluorinated motifs of interest in medicinal chemistry, was achieved through asymmetric transferhydrogenation of gem‐difluorocyclopropenyl esters, catalyzed by a Noyori–Ikariya (p‐cymene)‐ruthenium(II) complex, with (N‐tosyl‐1,2‐diphenylethylenediamine) as the chiral ligand and isopropanol
Chiral N,O-Ligand/[Cu(OAc)<sub>2</sub>]-Catalyzed Asymmetric Construction of 4-Aminopyrrolidine Derivatives by 1,3-Dipolar Cycloaddition of Azomethine Ylides with α-Phthalimidoacrylates
作者:Zheng Wang、Xingxin Yu、Bo-Xue Tian、Daniel T. Payne、Wu-Lin Yang、Yang-Zi Liu、John S. Fossey、Wei-Ping Deng
DOI:10.1002/chem.201500966
日期:2015.7.13
2‐a]pyridine motifs have been evaluated in the asymmetric 1,3‐dipolarcycloaddition of azomethineylides to α‐phthalimidoacrylates. Reactions catalyzed by copper in combination with ligand 7‐Cl‐DHIPOH provided the highest level of stereoselectivity for the 1,3‐dipolarcycloaddition reaction. The reaction tolerates both β‐substituted and β‐unsubstituted α‐phthalimidoacrylate as dipolarophiles, affording the
Nitration of phenylpropiolic acid derivatives in HSO3F and reactions of vinyl type cations formed therefrom
作者:P. Yu. Savechenkov、A. P. Rudenko、A. V. Vasil?ev
DOI:10.1007/s11178-005-0070-9
日期:2004.11
Nitration of phenylpropiolic acid derivatives ArC≡CX (X=CN, CO2Me) in HSO3F at −75...−50°C afforded mononitro compounds, for instance, m-O2NC6H4C≡CX. Vinyl type cations generated in HSO3F from methyl 3-arylpropiolates ArC+=CHCO2Me react along two pathways. The first among them results in formation of fluorosulfonates ArC(OSO2F)=CHCO2Me, and the second one after the attack of vinyl cation on the aryl moiety of the substrate affords a dimer that on nitration is converted into a nitro product with conserved triple bond.