A Recyclable Palladium-Catalyzed Synthesis of 2-Methylene-2,3-Dihydrobenzofuran-3-ols by Cycloisomerization of 2-(1-Hydroxyprop-2-ynyl)phenols in Ionic Liquids
Highly Efficient Activation of Organosilanes with η2-Aldehyde Nickel Complexes: Key for Catalytic Syntheses of Aryl-, Vinyl-, and Alkynyl-Benzoxasiloles
摘要:
An eta(2)-aldehyde nickel complex was utilized as an effective activator for an organosilane in order to generate a hypervalent silicate reactant for the first time. This method was successfully applied to the highly efficient syntheses of 3-aryl-, vinyl-, and alkynyl-2,1-benzoxasiloles from benzaldehydes with aryl-, vinyl-, and alkynylsilyl groups at the ortho position. Initial mechanistic studies revealed that an intermolecular aryl transfer process was involved in the reaction mechanism. The formation of an eta(2)-aldehyde complex was directly confirmed by NMR.
Copper-Catalyzed Dehydrative Cyclization of 1-(2-Hydroxyphenyl)propargyl Alcohols with P(O)H Compounds for the Synthesis of 2-Phosphorylmethylbenzofurans
A tetrakis(acetonitrile)copper(I) hexafluorophosphate [Cu(MeCN)PF6]‐catalyzed dehydrative reaction of 1‐(2‐hydroxyphenyl)propargyl alcohols with diarylphosphine oxides has been developed to provide an efficient synthesis of phosphorylated benzofurans in good to high yields. In the presence of a catalytic amount of an organic base, a variety of H‐phosphonates and H‐phosphinates can also be employed
Copper(I)-Catalyzed Hydroalkoxylation/Hydrogen-Bonding-Induced Asymmetric Hetero-Diels-Alder Cycloaddition Cascade: An Approach to Aromatic Spiroketals
作者:Xin Li、Jijun Xue、Chusheng Huang、Ying Li
DOI:10.1002/asia.201101056
日期:2012.5
One thing leads to another: Bis(benzannelated) 5,6‐spiroketal skeletons can be constructed by an efficient cascade process involving an unprecedented CuI‐catalyzed intramolecular alkyne hydroalkoxylation and an asymmetric hetero‐Diels–Alder cycloaddition. The method yields a series of diversely functionalized spiroketals from two readily available open‐chained starting materials in good yields and
A New Copper(I)-Catalyzed Cycloetherification/Acid-Catalyzed Allylic Nucleophilic Substitution for One-Pot Synthesis of 2-Substituted Benzofurans
作者:Jijun Xue、Ying Li、Xin Li、Rui Chen
DOI:10.1055/s-0031-1290767
日期:2012.4
A new copper(I)-catalyzed cycloetherification followed by an acid-catalyzed allylic nucleophilic substitution have been developed for the one-potsynthesis of 2-substituted benzofurans. This one-pot reaction proceeds efficiently under extremely mild conditions with simple and inexpensive catalysts, providing diversely substituted benzofurans in good to excellent yields.
Acid-Catalysed or Radical-Promoted Allylic Substitution of 2-Methylene-2,3-dihydrobenzofuran-3-ols with Thiol Derivatives: a Novel and Expedient Synthesis of 2-(Thiomethyl)benzofurans
The 2-thiomethylbenzofuran derivatives 3 are conveniently prepared in good yields through the reactions between the readily available 2-methylene-2,3-dihydrobenzofuran-3-ols 1 and the thiolderivatives 2 (including alkyl thiols, thiophenol, and thioacetic acid). The allylicsubstitution process may be either acid-catalysed or promoted by radical initiators. In the first case, the reactions are carried
通过易得的2-亚甲基-2,3-二氢苯并呋喃-3-醇1和硫醇衍生物2(包括烷基硫醇、苯硫酚和硫代乙酸)之间的反应,可以方便地以良好的产率制备2-硫甲基苯并呋喃衍生物3。烯丙基取代过程可以由酸催化或由自由基引发剂促进。在第一种情况下,反应在作为质子源的 H 2 SO 4 存在下,在 1,2-二甲氧基乙烷 (DME) 作为溶剂中,在 90 °C 下进行。在偶氮双(异丁腈)(AIBN)或过氧化苯甲酰(BP)作为自由基引发剂的存在下,自由基促进反应发生在 90 °C 的 DME 中。
A Novel Synthesis of 2-Functionalized Benzofurans by Palladium-Catalyzed Cycloisomerization of 2-(1-Hydroxyprop-2-ynyl)phenols Followed by Acid-Catalyzed Allylic Isomerization or Allylic Nucleophilic Substitution
furans 3 and 2-alkoxymethylbenzofurans 4-6, based on palladium-catalyzed cycloisomerization of 2-(1-hydroxyprop-2-ynyl)phenols 1 under basic conditions to give 2-methylene-2,3-dihydrobenzofuran-3-ols 2, followed by acid-catalyzed isomerization or allylic nucleophilic substitution with alcohols as nucleophiles, is reported. Cycloisomerization reactions leading to 2 (80-98% yields) were carried out at