A novel, efficient Z-alkene synthesis via photocatalyzed decarboxylative couplings between terminal aryl alkynes and alkyl N-hydroxyphthalimide (NHPI) esters, which are derived from aliphatic carboxylic acids, is described. A wide range of primary, secondary, and tertiary carboxylates as well as α-amino acid and α-oxyacid-derived esters were employed as suitable substrates. The mild reaction conditions
<i>Cis</i>-Selective Decarboxylative Alkenylation of Aliphatic Carboxylic Acids with Vinyl Arenes Enabled by Photoredox/Palladium/Uphill Triple Catalysis
An iridium photoredox catalyst in combination with phenanthroline-supported palladium catalyst catalyzes decarboxylative alkenylation of tertiary and secondary aliphatic carboxylicacids with vinyl arenes to deliver β-alkylated styrenes with Z-selectivity. A broad scope of aliphatic carboxylicacids, including amino acids, exhibit as amenable substrates, and external oxidant is not required. The reaction
A silver-catalyzed carbomagnesiation of alkynes with alkyl halides and Grignardreagents afforded alkenyl Grignardreagentsregioselectively, where the alkyl group of the alkyl halide, but not that of the Grignardreagent, was introduced into the alkyne. Application to δ-haloalkylacetylenes yielded cyclopentanes or a tetrahydrofuran containing an exo-methylene substituent via 5-exo-dig cyclization
Rhodium‐Catalyzed Regio‐ and Diastereoselective [3+2] Cycloaddition of <i>gem</i>‐Difluorinated Cyclopropanes with Internal Olefins
作者:Yaxin Zeng、Ying Xia
DOI:10.1002/anie.202307129
日期:2023.8.7
A rhodium-catalyzed [3+2] cycloaddition reaction between readily available gem-difluorinated cyclopropanes and internal olefins has been developed, providing a wide range of multisubstituted gem-difluorinated cyclopentanes. This reaction shows an example where the “CF2” motif can be kept upon ring extension. The process is atom-economic and allows to reach numerous gem-difluorinated cyclopentanes with
An Organocatalytic System for Z-Alkene Synthesis via a Hydrogen-Bonding-Assisted Photoinduced Electron Donor–Acceptor Complex
作者:Hui Zhao、Yingxiao Zong、Yue Sun、Guanghui An、Junke Wang
DOI:10.1021/acs.orglett.4c00433
日期:2024.3.1
photoinduced electrondonor–acceptor (EDA) complex and energy transfer was developed. This mild and metal-free protocol allows facile access to various Z-alkenes. Mechanism studies revealed that the organophotocatalyst, 4-CzIPN, formed a distinct three-component EDA complex with redox-active esters and (C6H5O)2P(O)OH to trigger the photoredox catalysis. The E → Z isomerization was achieved via electron exchange
开发了一种用于光诱导电子供体-受体(EDA)复合物和能量转移组合的通用催化供体。这种温和且不含金属的方案可以轻松获得各种Z-烯烃。机理研究表明,有机光催化剂 4-CzIPN 与氧化还原活性酯和 (C 6 H 5 O) 2 P(O)OH 形成独特的三组分 EDA 复合物,以触发光氧化还原催化。 E → Z异构化是通过 4-CzIPN 的电子交换能量转移实现的。