calcium‐catalyzed direct reduction of propargylic alcohols and ethers has been accomplished by using triethylsilane as a nucleophilic hydride source. At room temperature a variety of secondary propargylic alcohols was deoxygenated to the corresponding hydrocarbons in excellent yields. Furthermore, for the first time, a catalytic deoxygenation of tertiary propargylic alcohols was generallyapplicable. The
Synthesis of Substituted 1,2-Dihydropyridines from Propargyl Vinyl Ethers and Allenic Vinyl Ethers by Gold-Catalyzed Claisen Rearrangement and 6π-Aza-electrocyclization
作者:Hao Wei、Yao Wang、Bin Yue、Peng-Fei Xu
DOI:10.1002/adsc.201000292
日期:2010.10.4
An efficient synthetic method was developed for the construction of substituted 1,2-dihydropyridines by gold-catalyzed tandem reactions. The key intermediates 2,4-dienals were generated from propargyl vinyl ethers or allenic vinyl ethers with gold catalysts. These two reactions involved the process of gold-catalyzed [3,3]-sigmatropic rearrangement/isomerization/amine condensation/6π-aza-electrocyclization
Harnessing Nucleophilicity of Allenol Ester with <i>p-</i>Quinone Methides via Gold Catalysis: Application to the Synthesis of Diarylmethine-Substituted Enones
作者:Brijesh M. Sharma、Jayant Rathod、Rajesh G. Gonnade、Pradeep Kumar
DOI:10.1021/acs.joc.8b01294
日期:2018.8.17
A gold(I)-catalyzed protocol for intermolecular 1,6-conjugate addition of nucleophilic allenol ester generated in situ through [3,3]-sigmatropicrearrangement with p-quinone methides (p-QMs) has been developed. The gold catalyst plays a dual role by the π-acid-triggered activation of alkynes and at the same time as a Lewis acid for activation of p-QMs toward nucleophilic attack. This method enables
One-Pot Synthesis of 1,2-Dihydropyridines: Expanding the Diverse Reactivity of Propargyl Vinyl Ethers
作者:Tobias Harschneck、Stefan F. Kirsch
DOI:10.1021/jo102545m
日期:2011.4.1
The catalyzed synthesis of 1,2-dihydropyridines starting from easily accessible propargyl vinyl ethers was realized. The reaction sequence involving a transition metal-catalyzed propargyl-Claisen rearrangement, a condensation step, and a Brønsted acid-catalyzed heterocyclization furnishes the highly substituted heterocycles in moderate to excellent yields. Additionally, a practical one-pot protocol
Palladium-Catalyzed Synthesis of 2,3-Dihydro-2-ylidene-1,4-benzodioxins
作者:Jean-Robert Labrosse、Paul Lhoste、Denis Sinou
DOI:10.1021/jo0103625
日期:2001.10.1
4-benzodioxins. The reaction is suggested to proceed by the formation of a (sigma-allenyl)palladium complex, followed by the intermolecular attack of the phenoxideion on this complex to generate a new (sigma-allyl)palladium complex in equilibrium with the corresponding (eta(3)-allyl)palladium complex. Intramolecular attack of the phenoxideion afforded the corresponding benzodioxan compound. This last