Samarium diiodide is a catalyst for the reaction of cyclic and acyclic tert-butyldimethylsilyl enoxysilanes with chelating imines. Reaction products are isolated as β-aminoenoxysilanes instead of β-aminoketones as previously observed with the corresponding trimethylsilyl enoxysilanes. Several mechanistic pathways are discussed.
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。
Visible-Light-Mediated Amination of π-Nucleophiles with <i>N</i>-Aminopyridinium Salts
N-Aminopyridinium salts generate nitrogen-centered radicals by means of photoredox catalysis. Herein, we report that they can be trapped by enol equivalents to give α-amino carbonyl compounds in excellent yields. The broad syntheticutility of this method is demonstrated by functionalization of ketones, aldehydes, esters enol equivalents, vinyl ethers, and 1,3-diketones without the need for prior conversion
Room-Temperature, Acid-Catalyzed [2+2] Cycloadditions: Suppression of Side Reactions by using a Flow Microreactor System
作者:Kei Kurahashi、Yoshiji Takemoto、Kiyosei Takasu
DOI:10.1002/cssc.201100373
日期:2012.2.13
Added value: The [2+2] cycloaddition of silyl enolethers with α,β‐unsaturated esters, catalyzed by the superstrong acid triflic imide (Tf2NH), at roomtemperature in a flow microreactor system is reported. The micororeactor method achieves the [2+2] cycloaddition of unstable silyl enolethers and acrylates, which is unsuccessful in batch reactors, even at roomtemperature.
A Practical Catalytic Method for Preparing Highly Substituted Cyclobutanes and Cyclobutenes
作者:Kazato Inanaga、Kiyosei Takasu、Masataka Ihara
DOI:10.1021/ja042661s
日期:2005.3.1
efficiently catalyzes (2 + 2) cycloaddition reactions of silyl enol ethers with acrylates or propiolate. The process affords highly substituted cyclobutanes in high yield with high stereoselectivity under practical and environmentally benign conditions. Application for the formation of terpene skeletons and multigram synthesis of four-membered carbocycles were demonstrated.