palladium-catalyzed three-component cascade reaction has been developed for the facile construction of phenanthrene frameworks. The transformation is driven by a controlled reaction sequence of Suzuki–Miyaura coupling followed by the insertion of alkynes, and finally, annulation to yield phenanthrene derivatives via C–H activation. This methodology is able to accommodate a variety of substrates and affords
design and synthesis of stable 1,2-dithietane derivatives for the generation of diatomicsulfur (S 2 ) was undertaken. Computer-aided evaluation of enthalpic differences was used to direct the synthesis of target compounds and, although all of the compounds calculated to afford S 2 that were prepared did yield diatomicsulfur, an isolable 1,2-dithietane other than dithiatopazine failed to materialize
对用于生成双原子硫 (S 2 ) 的稳定 1,2-二硫杂环丁烷衍生物的设计和合成进行了详细研究。焓差的计算机辅助评估用于指导目标化合物的合成,尽管计算出的所有化合物均能提供所制备的 S 2 确实产生了双原子硫,但除二硫托嗪之外的可分离 1,2-二硫杂环丁烷未能实现
Synthesis of Multiply Substituted Polycyclic Aromatic Hydrocarbons by Iridium-Catalyzed Annulation of Ring-Fused Benzocyclobutenol with Alkyne through C−C Bond Cleavage
作者:Jiajia Yu、Hong Yan、Chen Zhu
DOI:10.1002/anie.201509973
日期:2016.1.18
iridium‐catalyzed intermolecular cyclization between alkynes and ring‐fused benzocyclobutenols (RBCB) through C−C bond cleavage is described. A variety of elusive polycyclic aromatic hydrocarbons (PAHs) with multiple substituents are obtained in good yields under mild conditions. This procedure provides a unique and expeditious tool for the synthesis of PAHs.
A rhodium-catalyzedannulative coupling of (2-arylphenyl)boronic acids with alkynes has been developed for the facile construction of phenanthrene frameworks. The reaction proceeded without external bases, and dioxygen worked as a terminal oxidant. Deuterium-labeling experiments indicated the involvement of five-membered rhodacycle intermediates.
Palladium-catalyzed double cross-coupling reaction of 1,2-bis(pinacolatoboryl)alkenes and -arenes with 2,2′-dibromobiaryls: annulative approach to functionalized polycyclic aromatic hydrocarbons
This study demonstrates that the doublecross-coupling reaction of 1,2-bis(pinacolatoboryl)alkenes and -arenes with 2,2′-dibromobiaryls proceeds smoothly with the aid of a catalytic amount of Pd(PPh3)4 in the presence of excess base to give a variety of polycyclic aromatic hydrocarbons, such as phenanthrenes, [5]helicene, dithienobenzenes, triphenylenes, dibenzo[g,p]chrysenes, and triphenyleno[1,2-b:4
这项研究表明,在催化量的Pd(PPh 3)4存在下,1,2-双(频哪醇硼基)烯烃和-芳烃与2,2'-二溴联芳基的双交叉偶联反应可以顺利进行。过量的碱可得到各种多环芳烃,例如菲,[5]螺旋烯,二硫代苯,三苯撑,二苯并[ g,p ],和三苯并[1,2- b:4,3- b ']二噻吩好到高产。值得注意的是,使用2,2'-二溴八氟联苯作为亲电试剂的环化反应提供了否则难以合成的八氟菲和半氟化二苯并[ g,p] chrysenes高产。