Nickel–NHC-Catalyzed Cross-Coupling of 2-Methylsulfanylbenzofurans with Alkyl Grignard Reagents
摘要:
NiCl2(PPh3)(IPr) catalyzes cross-coupling reactions of 2-methylsulfaylbenzofurans with alkyl Orignard reagents. Other nickel complexes such as NiCl2(dppe) failed to catalyze the same reaction. The alkylation is applicable to the synthesis of a couple of protein tyrosine phosphatase inhibitors, 3-(4-biphenylyl)-2-alkylbenzofurans.
Palladium-Catalyzed Zinc-Amide-Mediated CH Arylation of Fluoroarenes and Heteroarenes with Aryl Sulfides
作者:Shinya Otsuka、Hideki Yorimitsu、Atsuhiro Osuka
DOI:10.1002/chem.201502101
日期:2015.10.12
heteroarenes with aryl sulfides proceeds smoothly with the aid of a palladium–N‐heterocyclic carbene catalyst. A bulky zinc amide, TMPZnCl⋅LiCl, plays a key role as an effective base to generate the corresponding arylzinc species in situ. This arylation protocol is practically much easier to perform than our previous method, which necessitates preparation of the arylzincreagents in advance from the corresponding
Ç polyfluoroarenes和杂芳烃的与芳基硫化物ħ芳基化用钯- N-杂环卡宾催化剂的帮助下顺利进行。甲笨重锌酰胺,TMPZnCl ⋅的LiCl,起着以原位产生相应的芳基锌物种的有效碱关键作用。该芳基化方案实际上比我们以前的方法更容易执行,后者需要从相应的芳基卤化物预先制备芳基锌试剂。通过硫特异性反应(如S N Ar磺酰化反应和扩展的Pummerer反应)制备的芳基硫化物会经历这种直接芳基化,从而提供有趣的转化,而这些转化是传统的基于卤素的有机合成难以实现的。
Pd-NHC-Catalyzed Alkynylation of General Aryl Sulfides with Alkynyl Grignard Reagents
Cross‐coupling reactions of unactivated aryl sulfides with alkynylmagnesium chloride have been invented to afford 1‐aryl‐1‐alkynes with the aid of a palladium/N‐heterocyclic carbene complex. This reaction has by far the widest scope of all transformations utilizing aryl sulfides and alkynes, while known cross‐coupling alkynylations of aryl‐sulfur electrophiles require activated azaaryl sulfides, thiolactams
Palladium catalyzed Suzuki cross-coupling of 3-iodo-2-(methylthio)-benzo[b]furan derivatives: synthesis of 3-aryl-2-(methylthio)benzo[b]furans
作者:Rafaela M Gay、Flávia Manarin、Ricardo Brandão、Gilson Zeni
DOI:10.1590/s0103-50532010000900006
日期:——
A selective and efficient method for the synthesis of 3-aryl-2-(methylthio)benzo[ b]furans derivatives by palladiumcatalyzed cross-coupling reaction with boronic acids has been developed. The reaction proceeded cleanly under mild conditions and was performed with aryl boronic acids bearing electron-withdrawing, electron donating and neutral substituents.
Electrophilic Cyclization of 2-Chalcogenealkynylanisoles: Versatile Access to 2-Chalcogen-benzo[<i>b</i>]furans
作者:Flávia Manarin、Juliano A. Roehrs、Rafaela Mozzaquatro Gay、Ricardo Brandão、Paulo H. Menezes、Cristina W. Nogueira、Gilson Zeni
DOI:10.1021/jo802736e
日期:2009.3.6
An efficient synthesis of 2-chalcogen-3-substituted-benzo[b]furan compounds has been accomplished via electrophilic cyclization reaction of 2-chalcogenealkynyl anisoles using I-2, ICl, Br-2 and PhSeBr as electrophile sources. The product distributions were strongly dependent on the nature of substituents in the aromatic ring of anisole and on the chalcogen atom directly bonded to the triple bond. The 2-chalcogen-3-iodo-benzo[b]furans obtained smoothly underwent conversion to more complex structures of benzo[b]furan derivatives via palladium- or copper-catalyzed cross-coupling reaction with thiols, diphenyl diselenides, and zincates.
Generation of Organozinc Reagents from Arylsulfonium Salts Using a Nickel Catalyst and Zinc Dust
作者:Kodai Yamada、Tomoyuki Yanagi、Hideki Yorimitsu
DOI:10.1021/acs.orglett.0c03782
日期:2020.12.18
powder under nickel catalysis via the selective cleavage of the sp2-hybridized carbon–sulfur bond to produce salt-free arylzinc triflates undermildconditions. This zincation displays superb chemoselectivity and thus represents a protocol that is complementary or orthogonal to existing methods. The generated arylzincreagents show both high reactivity and chemoselectivity in palladium-catalyzed and copper-mediated