Stereoselective Alkene Isomerization over One Position
作者:Casey R. Larsen、Douglas B. Grotjahn
DOI:10.1021/ja3036477
日期:2012.6.27
Although controlling both the position of the double bond and E:Z selectivity in alkene isomerization is difficult, 1 is a very efficient catalyst for selective mono-isomerization of a variety of multifunctional alkenes to afford >99.5% E-products. Many reactions are complete within 10 min at room temperature. Even sensitive enols and enamides susceptible to further reaction can be generated. Catalyst
作者:Andrew L. Kocen、Maurice Brookhart、Olafs Daugulis
DOI:10.1039/c7cc04953f
日期:——
We report a method for palladium-catalysed chain-running isomerization of terminal and internal alkenes. Using an air-stable 2,9-dimethylphenanthroline-palladium catalyst in combination with NaBAr4 promoter, olefins are converted to the most stable double bond isomer at −30 to 20 °C. Silyl enol ethers are readily formed from silylated allylic alcohols. Fluorinated substituents are compatible with the
Copper-Catalyzed Formal Dehydrogenative Coupling of Carbonyls with Polyfluoroarenes Leading to β-C–H Arylation
作者:Weilong Xie、Dongwook Kim、Sukbok Chang
DOI:10.1021/jacs.0c10904
日期:2020.12.9
We herein communicate a formal dehydrogenativecoupling of carbonyls with polyfluoroarenes enabled by Cu catalysis. Silyl enol ethers initially prepared from carbonyls are postulated to undergo the copper-mediated oxidative dehydrogenativecoupling with polyfluoroarenes via a radicalpathway. Including cyclic and linear ketones, aldehydes, and esters, a broad range of β-aryl carbonyl products were
我们在此交流了通过 Cu 催化实现的羰基与多氟芳烃的正式脱氢偶联。假设最初由羰基化合物制备的甲硅烷基烯醇醚通过自由基途径与多氟芳烃进行铜介导的氧化脱氢偶联。包括环状和线性酮、醛和酯在内,以高区域和立体选择性和优异的官能团耐受性有效地获得了广泛的 β-芳基羰基产物。
Polarity-Reversed Addition of Enol Ethers to Imines under Visible Light: Redox-Neutral Access to Azide-Containing Amino Acids
作者:Sen Yang、Shuangyu Zhu、Dengfu Lu、Yuefa Gong
DOI:10.1021/acs.orglett.9b03238
日期:2019.10.18
established for the construction of γ-azido aminoacids under visiblelight. This transformation features mild and redox-neutral conditions, affording a series of amino esters with excellent chemoselectivity. Preliminary mechanistic studies revealed that the addition of an oxyalkyl radical to imine is likely the rate-determining step. The obtained azido-containing amino esters could be successfully converted
Radical-chain isomerisation of allyl silyl ethers to silyl enol ethers in the presence of thiols as polarity reversal catalysts
作者:Alistair J Fielding、Brian P Roberts
DOI:10.1016/s0040-4039(01)00630-x
日期:2001.6
radical-chain isomerisation of allylsilylethers to silyl enol ethers takes place on heating in the presence of an initiator and an arenethiol as a protic polarity reversal catalyst; pentafluorothiophenol is particularly effective in this role. The reaction complements the transition-metal-catalysed isomerisation and could be useful for the preparation of silyl enol ethers from readily available allylic