Titania-Catalyzed Radiofluorination of Tosylated Precursors in Highly Aqueous Medium
摘要:
Nucleophilic radiofluorination is an efficient synthetic route to many positron-emission tomography (PET) probes, but removal of water to activate the cyclotron-produced [F-18]fluoride has to be performed prior to reaction, which significantly increases overall radiolabeling time and causes radioactivity loss. In this report, we demonstrate the possibility of F-18-radiofluorination in highly aqueous medium. The method utilizes titania nanoparticles, 1:1 (v/v) acetonitrile-thexyl alcohol solvent mixture, and tetra-n-butylammonium bicarbonate as a phase-transfer agent. Efficient radiolabeling is directly performed with aqueous [F-18]fluoride without the need for a drying/azeotroping step to significantly reduce radiosynthesis time. High radiochemical purity of the target compound is also achieved. The substrate scope of the synthetic strategy is demonstrated with a range of aromatic, aliphatic, and cydoaliphatic tosylated precursors.
Nickel(0)-Catalyzed Cross-Coupling of Alkyl Arenesulfonates with Aryl Grignard Reagents
作者:Chul-Hee Cho、Hee-Sung Yun、Kwangyong Park
DOI:10.1021/jo026449n
日期:2003.4.1
nickel-catalyzed cross-coupling reactions of neopentyl arenesulfonates with arylmagnesium bromides, involving nucleophilic aromatic substitution of alkyloxysulfonyl groups by aryl nucleophiles, take place in high yields. Optimal efficiencies are obtained by adding 3 + 2 equiv of the Grignardreagent to a mixture of dppfNiCl(2) and the sulfonate in refluxing THF. Neopentyl arenesulfonates are useful sources of
[EN] METAL OXIDE CATALYZED RADIOFLUORINATION<br/>[FR] RADIOFLUORATION CATALYSÉE PAR OXYDE MÉTALLIQUE
申请人:UNIV CALIFORNIA
公开号:WO2016004377A1
公开(公告)日:2016-01-07
Inter alia, the first titania-catalyzed [18F]-radiofluorination in highly aqueous medium is provided. In embodiments, the method utilizes titanium dioxide, 1 : 1 acetonitrile- thexyl alcohol solvent mixture and tetrabutylammonium bicarbonate as a base. Radiolabeling may be directly performed with aqueous [18F]fluoride without the need for drying/azeotroping step, which reduces radiosynthesis time while keeping high fluoride conversion. The general applicability of the synthetic strategy to the synthesis of the wide range of PET probes from tosylated precursors is demonstrated.
C(sp<sup>3</sup>)–H Ritter amination by excitation of <i>in situ</i> generated iodine(<scp>iii</scp>)–BF<sub>3</sub> complexes
作者:Rok Narobe、Kathiravan Murugesan、Christoph Haag、Tobias Emanuel Schirmer、Burkhard König
DOI:10.1039/d2cc03283j
日期:——
Visible light excitation of iodine(III)–BF3 complex enables the formation of carbocations from C(sp3)–H bonds. The complexes are generated catalytically from iodoarene, carboxylate ligand, the oxidizing agent Selectfluor, and the Lewis acid BF3. This modular catalytic system allows the formation of synthetically valuable amine derivatives without a metal- or photocatalyst.
Copper-Catalyzed Oxidative C–C Bond Cleavage of Alkyl-(Hetero)arenes Enabling Direct Access to Nitriles
作者:Gaijun Xue、Fukai Xie、Hongliang Liang、Guoliang Chen、Wen Dai
DOI:10.1021/acs.orglett.2c02238
日期:2022.8.5
The cleavage and functionalization of C–C bonds has emerged as a powerful tool for discovery of new transformations. Herein, we report a protocol that enables direct synthesis of nitriles via copper-catalyzed oxidative cleavage and cyanation of C–C bonds in a wide variety of multicarbon alkyl-substituted (hetero)arenes. Detailed mechanistic studies reveal that a tandem oxidative process is involved