Catalytic ring expansion, contraction, and metathesis-polymerization of cycloalkanes
作者:Ritu Ahuja、Sabuj Kundu、Alan S. Goldman、Maurice Brookhart、Brian C. Vicente、Susannah L. Scott
DOI:10.1039/b712197k
日期:——
Tandem dehydrogenation-olefin-metathesis catalyst systems, comprising a pincer-ligated iridium-based alkane dehydrogenation catalyst and a molybdenum-based olefin-metathesis catalyst, are reported to effect the metathesis-cyclooligomerization of cyclooctane and cyclodecane to give cycloalkanes with various carbon numbers, predominantly multiples of the substrate carbon number, and polymers.
Starting from small cyclic ketones, continuous flow synthesis is used to produce medium-sized rings and macrocycles that are relevant for the fragrance industry. Triperoxides are important intermediates in this process and are pyrolyzed at temperatures above 250 °C. The synthesis is carried out in two continuously operated flow reactors connected by a membrane-operated separator. The practicality of
从小环酮开始,连续流动合成用于生产与香料工业相关的中型环和大环。三过氧化物是该过程中的重要中间体,可在 250 °C 以上的温度下热解。合成是在两个连续操作的流动反应器中进行的,这些反应器由膜操作的分离器连接。在这项工作中,通过使用危险的试剂混合物(30% H 2 O 2、65% HNO 3)和同样有问题的过氧化物的热解,令人印象深刻地证明了流动化学的实用性。所有新的大环化合物都进行了与麝香相关的嗅觉特性测试。
Cyclooctane Metathesis Catalyzed by Silica-Supported Tungsten Pentamethyl [(SiO)W(Me)<sub>5</sub>]: Distribution of Macrocyclic Alkanes
作者:Nassima Riache、Emmanuel Callens、Manoja K. Samantaray、Najeh M. Kharbatia、Muhammad Atiqullah、Jean-Marie Basset
DOI:10.1002/chem.201403704
日期:2014.11.10
Metathesis of cyclic alkanes catalyzed by the new surface complex [(SiO)W(Me)5] affords a wide distribution of cyclic and macrocyclic alkanes. The major products with the formula CnH2n are the result of either a ringcontraction or ringexpansion of cyclooctane leading to lower unsubstituted cyclic alkanes (5≤n≤7) and to an unprecedented distribution of unsubstituted macrocyclic alkanes (12≤n≤40)