Manganese(II)/Picolinic Acid Catalyst System for Epoxidation of Olefins
作者:Ross A. Moretti、J. Du Bois、T. Daniel P. Stack
DOI:10.1021/acs.orglett.6b00518
日期:2016.6.3
An in situ generated catalyst system based on Mn(CF3SO3)2, picolinic acid, and peracetic acid converts an extensive scope of olefins to their epoxides at 0 °C in <5 min, with remarkable oxidant efficiency and no evidence of radical behavior. Competition experiments indicate an electrophilic active oxidant, proposed to be a high-valent Mn = O species. Ligand exploration suggests a general ligand sphere
基于Mn(CF 3 SO 3)2,吡啶甲酸和过氧乙酸的原位生成的催化剂体系在0°C下于<5分钟内将大量烯烃转化为环氧化物,具有显着的氧化效率并且没有自由基的迹象行为。竞争实验表明,一种亲电子活性氧化剂被认为是高价Mn = O物种。配体探索表明,一般的配体球基序有助于有效氧化。该方法以其简单性和使用廉价试剂来快速获得高附加值产品而得到强调。
Nickel-Catalyzed Reductive Amidation of Unactivated Alkyl Bromides
作者:Eloisa Serrano、Ruben Martin
DOI:10.1002/anie.201605162
日期:2016.9.5
A user‐friendly, nickel‐catalyzed reductive amidation of unactivated primary, secondary, and tertiary alkylbromides with isocyanates is described. This catalytic strategy offers an efficient synthesis of a wide range of aliphatic amides under mild conditions and with an excellent chemoselectivity profile while avoiding the use of stoichiometric and sensitive organometallic reagents.
Fluorinated Isatin Derivatives. Part 2. New <i>N</i>-Substituted 5-Pyrrolidinylsulfonyl Isatins as Potential Tools for Molecular Imaging of Caspases in Apoptosis
作者:Anil K. Podichetty、Stefan Wagner、Sandra Schröer、Andreas Faust、Michael Schäfers、Otmar Schober、Klaus Kopka、Günter Haufe
DOI:10.1021/jm8015014
日期:2009.6.11
Caspases are responsible for the execution of the cell death program and are potentially suitable targets for the specific imaging of apoptosis in vivo. A series of N-1-substituted analogues of the small molecule nonpeptide caspase inhibitor (S)-5-[1-(2-methoxymethylpyrrolidinyl)sulfonyl]isatin (1), which may be useful for the development of caspase-targeted radioligands, were synthesized and their inhibition potencies were evaluated in vitro. Two of the most powerful techniques to introduce fluorine into organic compounds, viz, bromofluorination of olefins and fluorohydrin synthesis by ring-opening of epoxides, were used. Most of the target compounds are potent inhibitors of the two effector caspases-3 and -7. Furthermore, the F-18-radiolabeled model compound (S)-1-[4-(1-[F-18]fluoro-2-hydroxyethyl)benzyl]-5-[1-(2-methoxymethyl-pyrrolidinyl)sulfonyl]isatin ([F-18]37), a putative tracer for the noninvasive imaging of apoptosis by positron emission tomography (PET) was synthesized by nucleophilic epoxide ring-opening of its precursor 36. The radiochemistry utilized in the F-18-fluorination reverted to carrier-added [F-18]Et3N center dot 3HF, a new fluorine-18 source for radiolabeling.
UTITA, MINORU;NAKAGAVA, KADZUYUKI
作者:UTITA, MINORU、NAKAGAVA, KADZUYUKI
DOI:——
日期:——
A Dehydrohalogenation Methodology for Synthesizing Terminal Olefins under Mild Conditions
作者:Donald Poirier、Marie Bérubé、Fatima Kamal、Jenny Roy
DOI:10.1055/s-2006-950204
日期:——
A new methodology for preparing terminal olefins in good yield by dehydrohalogenation of primary alkyl iodide with tetrabutylammonium fluoride in dimethyl sulfoxide at room temperature is presented. Optimization of the mild reaction conditions and assays on various alkyl iodides are described.