Strategy for Overcoming Full Reversibility of Intermolecular Radical Addition to Aldehydes: Tandem C–H and C–O Bonds Cleaving Cyclization of (Phenoxymethyl)arenes with Carbonyls to Benzofurans
作者:Hong-Xing Zheng、Xiang-Huan Shan、Jian-Ping Qu、Yan-Biao Kang
DOI:10.1021/acs.orglett.8b01207
日期:2018.6.1
An intermolecular addition of carbon radicals enabled by a cascade radical coupling strategy is developed. It includes an intermolecular alkyl radical addition to a carbonyl group followed by an intramolecular alkoxy radical addition to haloarenes and produces substituted benzofurans in high yields. The radical nature of this reaction is explored by radical trapping experiments and EPR analysis. The
Copper(I)-Catalyzed Coupling of Terminal Acetylenes with Aryl or Vinyl Halides
作者:D. Venkataraman、Pranorm Saejueng、Craig G. Bates
DOI:10.1055/s-2005-869893
日期:——
Synthetic protocols using copper(I) catalysts for the for- mation of diaryl acetylenes, 1,3-enynes, benzofurans and indoles are described. The acetylenic moiety is an important unit found in many compounds that are of pharmaceutical, biological and ma- terial interests. 1 Aryl acetylenes are constituent units in important conjugated polymers. 1c 1,3-Enynes are found in many biologically and pharmaceutically
A Brönsted acid-promoted trifluoromethylselenolation of benzofurans was disclosed by using Se-(trifluoromethyl) 4-methylbenzenesulfonoselenoate as a stable and easily prepared electrophilic trifluoromethylselenolating reagent. A wide range of SeCF3-substituted benzofuran derivatives were obtained in moderate to good yields with excellent regioselectivity. The tandem cyclization/trifluoromethylselenolation
Efficient Synthesis of Benzofurans Utilizing [3,3]-Sigmatropic Rearrangement Triggered byN-Trifluoroacetylation of Oxime Ethers: Short Synthesis of Natural 2-Arylbenzofurans
作者:Norihiko Takeda、Okiko Miyata、Takeaki Naito
DOI:10.1002/ejoc.200601001
日期:2007.3
synthetic method for the preparation of benzofurans has been developed. The key step of this method is the [3,3]-sigmatropic rearrangement of N-trifluoroacetyl-ene-hydroxylamines, which was triggered by acylation of oxime ethers. TFAA has been proved to be the best reagent to induce [3,3]-sigmatropic rearrangement for the synthesis of cyclic oracyclic dihydrobenzofurans. On the other hand, the TFAT-DMAP
Transition-metal-free base catalyzed intramolecular cyclization of 2-ynylphenols for efficient and facile synthesis of 2-substituted benzo[<i>b</i>]furans
作者:Yong Liu、Tao Lu、Wei-Fang Tang、Jian Gao
DOI:10.1039/c8ra03882a
日期:——
A transition-metal-free basecatalyzedintramolecular cyclization of 2-ynylphenols was developed for the facile synthesis of 2-substituted benzo[b]furans. Various 2-aryl and 2-alkyl substituted benzo[b]furans can be obtained with good to excellent yields using readily available Cs2CO3 as the catalyst under mild reaction conditions. The broad substrates scope and the typical maintenance of vigorous
开发了一种无过渡金属碱催化的 2-炔基酚分子内环化,用于简便合成 2-取代的苯并[ b ]呋喃。使用容易获得的 Cs 2 CO 3作为催化剂,在温和的反应条件下,可以以良好至优异的收率获得各种 2-芳基和 2-烷基取代的苯并[ b ]呋喃。广泛的底物范围和克级高效效率的典型维持使该协议成为合成 2-取代苯并[ b ]呋喃衍生物的潜在实用方法。