Transition-metal-free C–C σ-bond activation of α-aryl ketones and subsequent Zn-catalyzed intramolecular cyclization: synthesis of tetrasubstituted furans
作者:Yang Yuan、Hailu Tan、Lingkai Kong、Zhong Zheng、Murong Xu、Jiaqi Huang、Yanzhong Li
DOI:10.1039/c9ob00081j
日期:——
atom-economical protocol for the synthesis of tetrasubstituted furans has been developed. This process is realized through the tandem reactions of Cs2CO3 promoted C–C σ-bond activation of α-aryl ketones followed by Zn-catalyzed intramolecular cyclization. This represents the first example for the preparation of tetrasubstituted furans through rearrangement of molecular skeletons and subsequent transformations
已经开发了用于合成四取代呋喃的高度原子经济的方案。该过程是通过Cs 2 CO 3促进α-芳基酮的C–Cσ键活化,然后进行Zn催化的分子内环化的串联反应来实现的。这代表了通过分子骨架的重排和随后的转化制备四取代呋喃的第一个实例。温和的反应条件和易于获得的起始原料使该方案在有机合成中具有吸引力。
Calcium-catalyzed regioselective dehydrative cross-coupling of propargylic alcohols with 1,3-dicarbonyl compounds
A novel calcium-catalyzed in situ dehydrative cross-coupling reaction of propargylicalcohols with 1,3-dicarbonyl compounds was developed. This catalytic system can suppress the competitive Meyer–Schuster rearrangement, control regioselectivity, and enable the desired process to occur under solvent-free conditions at room temperature with water as the only byproduct. A variety of vicinal tertiary and
Synthesis of Substituted Tetrahydrocyclobuta[<i>b</i>]benzofurans by Palladium-Catalyzed Substitution/[2+2] Cycloaddition of Propargylic Carbonates with 2-Vinylphenols
作者:Masahiro Yoshida、Shoko Ohno、Kosuke Namba
DOI:10.1002/anie.201306903
日期:2013.12.16
Radical methods: The title reaction proceeds in the presence of a palladium catalyst to deliver substituted tetrahydrocyclobuta[b]benzofurans in a stereoselective manner (see scheme). A radical mechanism is discussed.
自由基方法:标题反应在钯催化剂的存在下进行,以立体选择性方式递送取代的四氢环丁[ b ]苯并呋喃(参见方案)。讨论了一种根本机制。
Direct cyclization of 1,3-diaryl propargylic alcohols with β-dicarbonyl compounds by palladium-boric acid dual-catalyst system
Palladium and boric acid-catalyzed cyclization of underivatized 1,3-diaryl propargylic alcohols with 1,3-cyclohexanediones has been developed. Boric acid plays a role for the efficient activation of the propargylic alcohols. Various substituted tetrahydrobenzofuranones were obtained in moderate to good yields. Reactions using 4-hydroxy-2-pyrones as the nucleophile also proceeded to afford the substituted
An efficient method to synthesize tetrasubstituted furans using simple starting materials such as propargylic alcohols and 1,3-dicarbonyl compounds has been developed. It was discovered that InCl3 could catalyze this transformation efficiently while other simple iron, copper and silver salts were proven to be ineffective. (C) 2008 Elsevier Ltd. All rights reserved.