Synthesis of 4-Ynamides and Cyclization by the Vilsmeier Reagent to Dihydrofuran-2(3H)-ones
摘要:
The room-temperature nucleophilic addition of vinyl azides to propargylic alcohols under BF3 center dot Et2O catalysis provides an efficient synthesis of 4-ynamides. The procedure is operationally convenient, shows broad substrate scope, and is viable for the synthesis of multifunctional 4-ynamides. Further, a Vilsmeier intramolecular cyclization of 4-ynamides into dihydrofuran-2(3H)-ones has also been discovered, which represents the first report of alkynes being used as the nucleophiles in Vilsmeier-type reactions.
para-Toluenesulfonic Acid Catalyzed Synthesis of Indenes via a Tandem Friedel–Crafts Alkylation/Hydroarylation of Tertiary Propargylic Alcohols with Electron-Rich Arenes
A simple protocol to synthesize indenes efficiently by PTSA catalyzed tandem Friedel–Crafts alkylation/hydroarylation of tertiary propargylic alcohol with electron-rich arenes is described. The desired indenes were obtained regioselectively in good to very good yields under mild reaction conditions. The allene intermediate was isolated to get an insight into the mechanistic pathway of the indene forming
Palladium(II)/N-Heterocyclic Carbene-Catalyzed Regioselective Heteroannulation of Tertiary Propargyl Alcohols and<i>o</i>-Haloanilines to form 2-Alkenylindoles
Monometallic and bimetallic palladium(II)/N‐heterocyclic carbene complexes appended with naphthalimide or bisnaphthalimide moieties were designed, synthesized, and characterized. Employment of these catalysts brings about the step‐economic and regioselective heteroannulation of tertiary propargyl alcohols with o‐haloanilines resulting in biologically and pharmaceutically relevant 2‐alkenylindoles. Basis
Y(OTf)3-Catalyzed Cascade Propargylic Substitution/Aza-Meyer–Schuster Rearrangement: Stereoselective Synthesis of α,β-Unsaturated Hydrazones and Their Conversion into Pyrazoles
concise method for the highly stereoselective synthesis of α,β-unsaturated hydrazones by the Y(OTf)3-catalyzed cascade propargylic substitution/aza-Meyer–Schuster rearrangement reaction of tertiary propargylic alcohols and p-toluenesulfonyl hydrazide under an air atmosphere is developed. A series of α,β-unsaturated hydrazones have been synthesized from simple and readily available starting materials
Propargylic Activation Across a Heterobimetallic Ir−Sn Catalyst: Nucleophilic Substitution and Indene Formation with Propargylic Alcohols
作者:Paresh Nath Chatterjee、Sujit Roy
DOI:10.1021/jo100189z
日期:2010.7.2
A nucleophilicsubstitution of propargylicalcohols with carbon (arene, heteroarene, and allyltrimethylsilane), sulfur (thiol), oxygen (alcohol), and nitrogen (sulfonamide) nucleophiles has been demonstrated using a high-valent [Ir(COD)(SnCl3)Cl(μ-Cl)]2 catalyst in 1,2-dichloroethane to afford the corresponding propargylic products in moderate to excellent yields. Alkyl or aryl substituted tertiary
An environmentally benign protocol that affords propargylic sulfones containing highly congested carbon centers from easily accessible alcohols and sulfinic acids with water as the only byproduct is reported. The reaction proceeded via an in situ dehydrative cross-coupling process by taking advantage of the synergetic actions of multiple hydrogen bonds rather than relying on an external catalyst and/or