Consequences of Affinity in Heterogeneous Catalytic Reactions: Highly Chemoselective Hydrogenolysis of Iodoarenes
摘要:
The catalytic hydrodeibdination reaction using molecular hydrogen and Pd/C has been revisited. It is shown, for the first time, that the chemoselectivity of this reaction is controlled by the high affinity of the iodinated compound for the catalyst. This reaction is compatible with most easily reducible functional groups (nitro, aldehyde, olefin, etc:). Using this reaction, the first general method for tritium labeling of 3-(triflubromethyl)-3-phenyldiazirine is described.
Silver-Catalyzed [2+1] Cyclopropenation of Alkynes with Unstable Diazoalkanes:<i>N</i>-Nosylhydrazones as Room-Temperature Decomposable Diazo Surrogates
作者:Zhaohong Liu、Qiangqiang Li、Peiqiu Liao、Xihe Bi
DOI:10.1002/chem.201605335
日期:2017.4.6
The [2+1] cycloaddition of alkynes with diazo compounds represents one of the most powerful and reliable methods for the construction of cyclopropenes. However, it remains a formidable challenge to accomplish the cyclopropenation of alkynes with non‐stabilized diazoalkanes, owing to the fact that such compounds are unstable and prone to detonation. Herein, we report a general silver‐catalyzed cyclopropenation
Cu-Catalyzed Esterification Reaction via Aerobic Oxygenation and C–C Bond Cleavage: An Approach to α-Ketoesters
作者:Chun Zhang、Peng Feng、Ning Jiao
DOI:10.1021/ja4085463
日期:2013.10.9
The Cu-catalyzed novel aerobic oxidativeesterification reaction of 1,3-diones for the synthesis of α-ketoesters has been developed. This method combines C-C σ-bond cleavage, dioxygen activation and oxidative C-H bond functionalization, as well as provides a practical, neutral, and mild synthetic approach to α-ketoesters which are important units in many biologically active compounds and useful precursors
已开发出用于合成 α-酮酯的 Cu 催化的新型 1,3-二酮有氧氧化酯化反应。该方法结合了 CC σ-键裂解、双氧活化和氧化 CH 键功能化,并为 α-酮酯提供了一种实用、中性和温和的合成方法,α-酮酯是许多生物活性化合物中的重要单元和各种有用的前体。功能组转换。在机理研究的基础上提出了一个合理的激进过程。
Synthesis of substituted α-methylene-γ-butyrolactones from chloroformates via palladium catalysed cyclisation–anion capture
作者:Ronald Grigg、Vladimir Savic
DOI:10.1039/b006842j
日期:——
Cyclisation of chloroformates onto proximate alkyne
functionality in the presence of a Pd(0) catalyst followed by
anion capture affords α-methylene-γ-butyrolactone derivatives
in moderate to good yields.
We have prepared a range of alkynyl benzoates in high yields and have investigated their reactivities with the strong Lewis acid B(C6F5)3. In such molecules both σ-activation of the carbonyl and π-activation of the alkyne are possible. In contrast to the reactivity of propargyl esters with B(C6F5)3 which proceed via 1,2-addition of the ester and B(C6F5)3 across the alkyne, the inclusion of an additional CH2 spacer switches off the intramolecular cyclization and selective σ-activation of the carbonyl group is observed through adduct formation. This change in reactivity appears due to the instability of the species which would be formed through B(C6F5)3 activation of the alkyne.
The catalytic hydrodeibdination reaction using molecular hydrogen and Pd/C has been revisited. It is shown, for the first time, that the chemoselectivity of this reaction is controlled by the high affinity of the iodinated compound for the catalyst. This reaction is compatible with most easily reducible functional groups (nitro, aldehyde, olefin, etc:). Using this reaction, the first general method for tritium labeling of 3-(triflubromethyl)-3-phenyldiazirine is described.