Living Alternating Ring-Opening Metathesis Polymerization Based on Single Monomer Additions
作者:Benjamin R. Elling、Yan Xia
DOI:10.1021/jacs.5b05497
日期:2015.8.12
modulating the ringstrain and sterics, we developed a class of disubstituted cyclopropenes that selectively underwent single monomer addition in ring-opening metathesis but readily underwent alternating ring-opening metathesispolymerization with low-strain cyclic olefins in a living fashion. The substituents on cyclopropenes effectively inhibited homoaddition and prevented secondary metathesis on the polymer
通过明智地调节环应变和空间位阻,我们开发了一类双取代环丙烯,它们在开环复分解中选择性地进行单一单体加成,但很容易以活性方式与低应变环烯烃进行交替开环复分解聚合。环丙烯上的取代基有效地抑制了均加成并防止了聚合物骨架上的二次复分解。所得聚合物在优化条件下具有可控的分子量和端基、极低的分散性和高的微观结构规则性。(1)H 和 (13)C NMR 光谱和 MALDI-TOF MS 显示出严格交替的序列。有趣的是,发现双取代的环丙烯呈现零级动力学,
Organocatalytic Carbonyl-Olefin Metathesis
作者:Allison K. Griffith、Christine M. Vanos、Tristan H. Lambert
DOI:10.1021/ja309650u
日期:2012.11.14
The development of a catalytic carbonyl-olefin metathesis strategy is reported, in the context of the ring-opening metathesis of cyclopropenes with aldehydes using a,simple hydrazine catalyst The key to this reaction is 4 conceptual blueprint for metathesis chemistry that forgoes the traditional reliance on [2 + 2] cycloaddition modes in favor of a [3 + 2] paradigm.
Enantioselective Palladium-Catalyzed Carbozincation of Cyclopropenes
作者:Katja Krämer、Paul Leong、Mark Lautens
DOI:10.1021/ol1029904
日期:2011.2.18
A highly enantioselective palladium-catalyzed carbozincation of cyclopropenes has been developed. The intermediate cyclopropylzinc species, after transmetalation with copper, were trapped with various electrophiles. This one-pot procedure furnished functionalizied cyclopropenes with excellent diastereo- and enantioselectivity.