that the synthesis of stereodefined 1,3-enynes featuring a trisubstituted olefin is achieved by merging alkynes, alkynyl bromides, and redox-active N-(acyloxy)phthalimides through nickel-catalyzed reductive alkylalkynylation. Products are generated in up to an 89% yield as single regio- and E isomers. Transformations are tolerant of diverse functional groups and the resulting 1,3-enynes are amenable
The intramolecularcarbolithiation of a series of propargylic ethers has been performed to evaluate the influence of the terminal substituent on the efficiency and the stereochemical outcome of the cyclization. Our results show that only 5-exo-dig cyclizations are observed, and dihydrobenzofurans are obtained exclusively. Depending on the nature of the terminal substituent, two cases can be considered
已经进行了一系列炔丙醚的分子内碳锂化,以评估末端取代基对环化效率和立体化学结果的影响。我们的结果表明,仅观察到 5-exo-dig 环化,并且仅获得了二氢苯并呋喃。根据末端取代基的性质,可以考虑两种情况。如果炔烃碳原子携带的末端取代基本身是碳原子,则只要末端炔丙基位置带有配位元素并且至少是二取代的,就可以发生环化。当环化发生时,它遵循反碳石化途径,从而导致环外双键的 E 异构体。仅在一种情况下(Ph)是回收的所得烯烃的E和Z异构体的混合物。如果调节环化条件,炔烃直接被 S 或 Si 取代,也可以发生环化。在三甲基甲硅烷基取代基的情况下,观察到顺式碳锂化。如果双键被恢复,在大多数情况下,在环外位置,产物可以直接芳构化为 SPh 取代的底物 24。此外,在后两种情况下,当进行乙烯基锂中间体的烷基化时,双键的异构化似乎是瞬间的。
Iron‐Mediated Cyclization of 1,3‐Diynyl Propargyl Aryl Ethers with Dibutyl Diselenide: Synthesis of Selenophene‐Fused Chromenes
作者:Guilherme Lutz、Davi F. Back、Gilson Zeni
DOI:10.1002/adsc.201901410
日期:2020.3.4
of selenophene‐fused chromene derivatives starting from 1,3‐diynyl propargyl aryl ethers is reported herein. The method is based on carbon‐carbon, carbon‐selenium, selenium‐carbon and carbon‐selenium bonds formation in a one‐pot protocol, using iron(III) chloride and dibutyl diselenide as promoters. The same reaction conditions were applied to propargyl anilines leading to the formation of 1‐(buty
Copper(II)-Catalyzed Amidations of Alkynyl Bromides as a General Synthesis of Ynamides and <i>Z</i>-Enamides. An Intramolecular Amidation for the Synthesis of Macrocyclic Ynamides
作者:Xuejun Zhang、Yanshi Zhang、Jian Huang、Richard P. Hsung、Kimberly C. M. Kurtz、Jossian Oppenheimer、Matthew E. Petersen、Irina K. Sagamanova、Lichun Shen、Michael R. Tracey
DOI:10.1021/jo060230h
日期:2006.5.1
method for the coupling of a wide range of amides with alkynyl bromides is described here. This novel amidation reaction involves a catalytic protocol using copper(II) sulfate-pentahydrate and 1,10-phenanthroline to direct the sp-C−N bond formation, leading to a structurally diverse array of ynamides including macrocyclic ynamides via an intramolecular amidation. Given the surging interest in ynamide chemistry
A systematic study of the behaviour of aryl γ-halopropargyl ethers under thermal condition was undertaken. Aryl γ-bromopropargyl ethers underwent unique transformation in N,N-diethylanillne (215°C, 6 h) giving rise to a mixture of products ,and , whereas, under similar conditions aryl γ-chloropropargyl ethers ulbar|8, afforded 4-chlorochromenes, 9. A remarkable substituent and solvent effect has been