of carboxylic acids. Herein, we reported the development of a palladium-catalyzed highly enantioselective Markovnikov hydroxycarbonylation of vinyl arenes with CO and water. A monodentate phosphoramidite ligand L6 plays vital role in the reaction. The reaction tolerates a range of functional groups, and provides a facile and atom-economical approach to an array of 2-arylpropanoic acids including several
不对称羟基羰基化是合成羧酸的最基本但最具挑战性的方法之一。在此,我们报道了钯催化的乙烯基芳烃与 CO 和水的高度对映选择性马尔可夫尼科夫羟基羰基化的发展。单齿亚磷酰胺配体L6反应中起重要作用。该反应耐受一系列官能团,并为一系列 2-芳基丙酸(包括几种常用的非甾体抗炎药)提供了一种简便且原子经济的方法。该催化体系还使乙烯基芳烃与醇发生不对称马尔科夫尼科夫氢烷氧基羰基化反应,得到 2-芳基丙酸酯。机理研究表明,氢化钯是不可逆的,是区域和对映体决定步骤,而水解/醇解可能是限速步骤。
Palladium-catalyzed regiodivergent hydroaminocarbonylation of alkenes to primary amides with ammonium chloride
作者:Bao Gao、Guoying Zhang、Xibing Zhou、Hanmin Huang
DOI:10.1039/c7sc04054g
日期:——
the synthesis of primary amides has long been an elusive aim. Here, we report an efficient catalytic system which enables inexpensive NH4Cl to be utilized as a practical alternative to gaseous ammonia for the palladium-catalyzed alkene-hydroaminocarbonylation reaction. Through appropriate choice of the palladium precursors and ligands, either branched or linear primary amides can be obtained in good
Palladium-catalyzed 1,1-alkynylbromination of alkenes with alkynyl bromides
作者:Yusuke Ano、Natsuki Kawai、Naoto Chatani
DOI:10.1039/d1sc02873a
日期:——
The palladium-catalyzed 1,1-alkynylbromination of terminal alkenes with a silyl-protected alkynyl bromide is reported. The method tolerates a diverse range of alkenes including vinylarenes, acrylates, and even electronically unbiased alkene derivatives to afford propargylic bromides regioselectively. Mechanistic studies and DFT calculations indicate that the 1,1-alkynylbromination reaction proceeds
Pd-Catalyzed Regioselective 1,2-Difunctionalization of Vinylarenes with Alkenyl Triflates and Aryl Boronic Acids at Ambient Temperature
作者:Zhijie Kuang、Kai Yang、Qiuling Song
DOI:10.1021/acs.orglett.7b01036
日期:2017.5.19
A Pd-catalyzed highly regioselective 1,2-difunctionalization of vinylarenes is disclosed in which multisubstituted olefins are efficiently and conveniently constructed under ambient temperature with good compatibility and a broad substrate scope. Notably, a quarternary carbon center could be readily built up from 1,1-disubstituted styrenes, which are big challenges in the previous methods.
Phosphonium Phenolate Zwitterion
<i>vs</i>
Phosphonium Ylide: Synthesis, Characterization and Reactivity Study of a Trimethylphosphonium Phenolate Zwitterion
作者:Jing Xiao、Qiang Li、Ruwei Shen、Shigeru Shimada、Li‐Biao Han
DOI:10.1002/adsc.201901303
日期:2019.12.17
CD3CN with substrates bearing weakly acidic hydrogens. It exhibits similar reactivity to phosphorus ylides for olefinations of aldehydes. A possible tautomerization between the phosphonium phenolate zwitterion and phosphonium ylide is proposed for the first time to rationalize the unique reactivity.