Syntheses of Tetrasubstituted [10]Cycloparaphenylenes by a Pd-catalyzed Coupling Reaction. Remarkable Effect of Strain on the Oxidative Addition and Reductive Elimination
Syntheses of Tetrasubstituted [10]Cycloparaphenylenes by a Pd-catalyzed Coupling Reaction. Remarkable Effect of Strain on the Oxidative Addition and Reductive Elimination
复制标题
DOI：
10.1002/asia.202000711
复制
发表时间：
2020-07-03
影响因子：
4.1
通讯作者：
Yamago, Shigeru
中科院分区：
文献类型：
--
作者：
Kayahara, Eiichi;Nakano, Masaya;Yamago, Shigeru
以四氟酸[10]CPP5 e为起始原料，通过钯催化的交叉偶联反应，构建了一个含有烷基、烯基、炔基和芳基的四取代[10]环芳基([10]CPP)衍生物小库，在a>；2g规模上高产率可得。根据竞争实验，CPP骨架增加了三氟代芳烃对钯物种的氧化加成反应活性，并且5 EIS的反应活性是其线性对苯类似物的10倍。理论计算表明，没有参与反应的每个对苯单元的小应变释放的积累是观察到的反应活性增强的原因。
A small library of tetrasubstituted [10]cycloparaphenylene ([10]CPP) derivatives bearing alkyl, alkenyl, alkynyl and aryl substituents was constructed by a Pd-catalyzed cross-coupling reaction starting from tetratriflate [10]CPP5 e, which was readily available in high yields on a >2 g scale. The CPP skeleton increases the reactivity of aryl triflate for oxidative addition to the Pd species, and5 eis 10 times more reactive than its linear paraphenylene analogue, as determined by competition experiments. Theoretical calculations suggest that the accumulation of the small strain relief from each paraphenylene unit not involved in the reaction is responsible for the observed enhanced reactivity.