The first base-promoted formal [4 + 3] annulation between 2-fluorophenylacetylenes and ketones has been disclosed. The reaction proceeds through a tandem α-vinylation of ketones followed by an intramolecular nucleophilic aromatic substitution (SNAr) reaction of the in situ generated β,γ-unsaturated ketone intermediates, providing a straightforward access to a wide range of functionalized benzoxepines
Electrooxidative Rhodium‐Catalyzed [5+2] Annulations via C−H/O−H Activations
作者:Yulei Wang、João C. A. Oliveira、Zhipeng Lin、Lutz Ackermann
DOI:10.1002/anie.202016895
日期:2021.3.15
five‐ and six‐membered heterocycles. In contrast, we herein describe the first electrochemical metal‐catalyzed [5+2] cycloadditions to assemble valuable seven‐membered benzoxepine skeletons by C−H/O−H activation. The efficient alkyne annulation featured ample substrate scope, using electricity as the only oxidant. Mechanistic studies provided strong support for a rhodium(III/I) regime, involving a
Rh(<scp>iii</scp>)-catalyzed (5 + 2)-cycloaddition reactions of <i>ortho</i>-hydroxyethyl phenols with internal alkynes: efficient synthesis of benzoxepines
作者:Pratiksha Bhorali、Jyotshna Phukon、Sanjib Gogoi
DOI:10.1039/d3ob00170a
日期:——
An unprecedented (5 + 2)-cycloaddition reaction of ortho-hydroxyethyl phenol and internal alkyne was developed. This Rh(III)-catalyzed reaction provided benzoxepine derivatives which have very high biological significance. A wide range of ortho-hydroxyethyl phenols and internal alkynes were studied to provide the benzoxepines in high yields.
开发了邻羟乙基苯酚和内炔烃的前所未有的 (5 + 2)-环加成反应。这种 Rh( III ) 催化的反应提供了具有非常高生物学意义的苯并氧庚因衍生物。研究了范围广泛的邻羟乙基苯酚和内部炔烃以提供高产率的苯并氧杂庚啶。
Dearomatization Silylation of Benzofurans and Furopyridines via Silyl Radical Addition and Endocyclic C–O Bond Scission
作者:Benqiang Cui、Ye Tian、Yongchao Gao、Shaoyi Hua、Yanhui Shi、Changsheng Cao
DOI:10.1021/acs.joc.3c01162
日期:2023.8.4
further derivatization reactions to achieve more valuable compounds. Cleavage of heteroaromatic endocyclic carbon–heteroatom bonds to assemble C–Si bonds is scarce. Here, we demonstrate a dearomatization silylation of benzofurans and furopyridines via silyl radical addition and C(2)–Obond scission under metal-catalyst-free and mild conditions. Preliminary mechanistic experiments suggest that these transformations
Straightforward Assembly of Benzoxepines by Means of a Rhodium(III)-Catalyzed C–H Functionalization of <i>o</i>-Vinylphenols
作者:Andrés Seoane、Noelia Casanova、Noelia Quiñones、José L. Mascareñas、Moisés Gulías
DOI:10.1021/ja410538w
日期:2014.1.22
Readily available o-vinylphenols undergo a formal (5 + 2) cycloaddition to alkynes when treated with catalytic amounts of [Cp*RhCl2](2) and Cu(OAc)(2). The reaction, which involves the cleavage of the terminal C-H bond of the alkenyl moiety, generates highly valuable benzoxepine skeletons in a practical, versatile, and atom-economical manner. Using carbon monoxide instead of an alkyne as reaction partner leads to coumarin products which formally result from a (5 + 1) cycloaddition.