The selective hydrogenolysis of C–O bonds in lignin model compounds by Pd–Ni bimetallic nanoparticles in ionic liquids
作者:Kang-kang Sun、Guo-ping Lu、Jia-wei Zhang、Chun Cai
DOI:10.1039/c7dt02498c
日期:——
bimetallic nanoparticles in ionic liquids using hydrogen gas as the hydrogen donor under ambient pressure and neutral conditions. No hydrogenation of benzene ring takes place in the catalyticsystem. A obvious improvement in activity is found compared with single nickel and palladium catalysts based on the results of experiments and characterization. After the reaction, the catalyticsystem still stays
A novel gold-catalyzed ethynylation of aromatic rings with electron-deficient alkynes via gold catalyzed C-H activation of both C(sp)-H and C(sp(2))-H bonds has been developed. This transformation provides aromatic propiolates difficult to prepare by other methods, highlighting the synthetic potential of gold chemistry.
Palladium-Catalyzed Dehydrogenative β′-Arylation of β-Keto Esters under Aerobic Conditions: Interplay of Metal and Brønsted Acids
作者:Kai-Tai Yip、Roshan Y. Nimje、Mikko V. Leskinen、Petri M. Pihko
DOI:10.1002/chem.201201988
日期:2012.10.1
The Brønsted aids: The first dehydrogenative arylation of β‐keto esters with arenes under ambient aerobic conditions is described (see scheme). Under a PdII/Brønstedacid co‐catalytic system, regioselective arylations with alkoxylated arenes and phenols were achieved in good yields, even in gram‐scale conditions.
布朗斯台德助剂:描述了在环境好氧条件下,β-酮酯与芳烃的第一次脱氢芳基化反应(参见方案)。在Pd II /布朗斯台德酸共催化体系下,即使在克级条件下,也能以良好的收率实现烷氧基化的芳烃和苯酚的区域选择性芳基化。
Shifted Selectivity in Protonation Enables the Mild Deuteration of Arenes Through Catalytic Amounts of Bronsted Acids in Deuterated Methanol
作者:Oliver Fischer、Anja Hubert、Markus R. Heinrich
DOI:10.1021/acs.joc.0c01604
日期:2020.9.18
effect” of the solvent methanol, deuterations of electron-rich aromatic systems can be carried out under mild acid catalysis and thus under far milder conditions than known so far. The exceptional functional group tolerance observed under the optimized conditions, which even includes highly acid-labile groups, results from a hitherto unexploited shifted selectivity in protonation, and enabled simple
Provided is a method for the preparation of a deuterated or tritiated aromatic compound via deuteration or tritiation of an aromatic starting compound which comprises an aromatic ring or a fused aromatic ring system which may be carbocyclic or hetercyclic and which carries at least one hydrogen atom directly bonded to a carbon ring atom of an aromatic ring, said method comprising:
a) providing a liquid composition wherein the aromatic starting compound is dissolved or dispersed in a deuterated or tritiated solvent which is not water, or in a solvent system comprising at least one deuterated or tritiated solvent which is not water; and
b) replacing at least one hydrogen atom directly bonded to a carbon ring atom of an aromatic ring comprised by the aromatic starting compound with deuterium or tritium via the transfer of at least one deuterium of tritium atom from the deuterated or tritiated solvent to the aromatic starting compound dissolved or dispersed in the liquid composition in the presence of an acid,
to convert the aromatic starting compound to a deuterated or tritiated aromatic compound which comprises an aromatic ring or a fused aromatic ring system which may be carbocyclic or hetercyclic and which carries at least one deuterium or tritium atom directly bonded to a carbon ring atom of an aromatic ring.
本发明提供了一种通过对芳香族起始化合物进行氚化或氚化来制备氚化或三氚化芳香族化合物的方法,所述芳香族起始化合物包括一个芳香环或一个可为碳环或杂环的融合芳香环系统,且至少携带一个与芳香环的碳环原子直接键合的氢原子,所述方法包括
a) 提供液体组合物,其中芳香族起始化合物溶解或分散在非水的氚代或三氚代溶剂中,或溶解或分散在包含至少一种非水的氚代或三氚代溶剂的溶剂体系中;以及
b) 在酸存在的情况下,通过将至少一个氘原子或氚原子从氚化或氚化溶剂转移到溶解或分散在液体组合物中的芳香族起始化合物,用氘原子或氚原子取代与芳香族起始化合物所包含的芳香环的碳环原子直接结合的至少一个氢原子、
将芳香族起始化合物转化为氚化或氚化芳香族化合物,该芳香族化合物包含一个芳香环或一个融合芳香环系统,该芳香环系统可以是碳环或杂环,并携带至少一个直接键合到芳香环碳环原子上的氘或氚原子。