A new mode of aromatic metamorphosis has been developed, which allows thiophenes and their benzo‐fused derivatives to be converted to a variety of exotic heteroles. This transformation involves 1) the efficient generation of key 1,4‐dianions by means of desulfurative dilithiation with lithium powder and 2) the subsequent trapping of the dianions with heteroatom electrophiles in a one‐pot manner. Via
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
2-Arylbenzoylchlorides undergo annulativecoupling with internal alkynes in the presence of a catalyst system of [IrCl(cod)]2/P(t-Bu)3 to selectively afford the corresponding phenanthrenederivatives accompanied by elimination of carbon monoxide and hydrogen chloride. The reaction occurs without addition of any external base. Deuterium-labeling experiments using 2-(d5-phenyl)benzoyl chloride suggest
Highly Efficient Route to Fused Polycyclic Aromatics via Palladium-Catalyzed Aryne Annulation by Aryl Halides
作者:Zhijian Liu、Richard C. Larock
DOI:10.1021/jo0619534
日期:2007.1.1
Polycyclic aromatic and heteroaromatic hydrocarbons have been synthesized in high yield by two different processes involving the Pd-catalyzed annulation of arynes. The first process involves a Pd-catalyzed annulation of arynes by 2-halobiaryls and related vinylic halides. The second process utilizes a Pd-catalyzed double annulation of arynes by simple aryl halides. Both processes appear to involve
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