Friedel−Crafts-Type Cyclization of 2,2-Difluorovinyl Ketones via α-Fluorocarbocations and Its Application in Domino Cyclizations
摘要:
2,2-Difluorovinyl ketones bearing an aryl group undergo Friedel-Crafts-type cyclization via carbocations stabilized by alpha-fluorines on treatment with a trimethylsilylating agent [Me3SiOTf or Me3SiB(OTf)(4)]. The reaction affords 4-fluorinated 3-acyl-1,2-dihydronaphthalenes, which are successfully subjected to a substitution-cyclodehydration process or a Nazarov-type cyclization to construct fused polycyclic systems.
Dual Functionalization of α‐Monoboryl Carbanions through Deoxygenative Enolization with Carboxylic Acids
作者:Wei Sun、Lu Wang、Chungu Xia、Chao Liu
DOI:10.1002/anie.201801679
日期:2018.5.4
1‐diborylalkanes through deoxygenative enolization with carboxylicacids was developed. 1,1‐Diborylalkanes were activated by MeLi to generate α‐monoboryl carbanions. In situ IR spectroscopy indicated an interaction between carboxylicacid and 1,1‐diborylalkane before addition of the activation reagent. Release of the active α‐monoboryl carbanion from the masked form was necessary for its reaction with carboxylate
Ligand-Free Palladium-Catalyzed Carbonylative Suzuki Couplings of Vinyl Iodides with Arylboronic Acids under Substoichiometric Base Conditions
作者:Zhiyuan Yang、Pei-Xue Gong、Wei Han、Junjie Chen、Jie Zhang、Xu Gong
DOI:10.1055/a-1511-0435
日期:2021.7
A ligand-free palladium-catalyzedcarbonylation of vinyl iodides with arylboronic acids, permitting the synthesis of chalcones and α-branched enones, has been established. This reaction proceeds smoothly at ambient pressure and temperature, and works well even with a substoichiometric amount of base. Importantly, this mild, efficient, and operationally simple protocol is suitable for the late-stage
Visible Light-Induced Deoxygenation and Allylation/Vinylation of Pyridyl Ethers
作者:Fan Wang、Yuwen Tang、Xiang Li、Jingtian Chen、Jingyue Yang
DOI:10.1021/acs.orglett.2c02756
日期:2022.10.14
The generation of alkyl radicals by deoxygenation of unactivated ethers under visible light catalysis is a hitherto unmet challenge. Herein, we report a visible light-induced deoxygenation of pyridyl ethers via formation of their pyridinium salts. The generated benzylic radicals further react with allyl/alkenyl sulfones to provide a series of coupling products in good to moderate yields. This process