Synthesis of Highly Substituted Racemic and Enantioenriched Allenylsilanes via Copper-Catalyzed Hydrosilylation of (<i>Z</i>)-2-Alken-4-ynoates with Silylboronate
Copper-catalyzed highly efficient hydrosilylation reaction of enynoates was developed. Under simple reaction conditions, various di-, tri-, and tetrasubstituted racemic allene products could be obtained in high yields. The asymmetric 1,6-addition of silyl group to the (Z)-2-alken-4-ynoates could be achieved under mild reaction conditions to afford the silyl-substituted enantioenriched chiral allene
The Pd(II)-catalyzed one-pot tandem cyclization/alkylation reactions of enynoates with allylic alcohols have been demonstrated. In this reaction, an innovative protocol proceeded well through Pd-catalyzed intramolecular selective 6-endo cyclization, insertion of allylic alcohols into the Pd–C bond of vinylpalladium species generated in situ, and β-hydrogen elimination processes. This conversion provides
A Pd(II)-catalyzed mild and highly regioselective 6-endo cyclization/allylation reaction of enynoates with simple allylic alcohols has been developed. Under mild reaction conditions, the vinyl palladium species generated in situ after cyclization could insert C–C double bond of allylic alcohol through cross-coupling reaction and lead to the formation of allyl pyrone via β-OH elimination. This cascade
Gold-Catalyzed Cyclization of Alkynylaziridines as an Efficient Approach toward Functionalized <i>N</i>-Phth Pyrroles
作者:Xiangwei Du、Xin Xie、Yuanhong Liu
DOI:10.1021/jo902357x
日期:2010.1.15
An efficient access to N-phth pyrrroles via gold-catalyzed cycloisomerization of N-phth alkynylaziridines has been described. Functionalized pyrroles including pyrrole-2-carboxylates or 2-pyrrolyl ketone are easily constructed in generally good yields by this method. The resulting pyrroles can be further converted to N-amino pyrrole or 2-acyl pyrrole, which are important synthetic intermediates for
Chemo-, Regio- and Stereoselective Tricyclohexylphosphine-Catalyzed [3+2] Cycloaddition of Enynes with [60]Fullerene Initiated by 1,4-Michael Addition: Synthesis of Cyclopenteno[60]fullerenes and their Electrochemical Properties
作者:Po-Yen Tseng、Shih-Ching Chuang
DOI:10.1002/adsc.201300255
日期:2013.8.12
AbstractHerein we demonstrate a tricyclohexylphosphine‐catalyzed cycloaddition of (E)‐ or (Z)‐alkyl 5‐substituted phenylpent‐2‐en‐4‐ynoates with [60]fullerene to give cyclopentenofullerenes in good to excellent yields, through initial chemo‐ and regioselective 1,4‐addition of phosphines at the β‐carbon of the enyne substrates. The nucleophilic addition pattern of P(cHx)3 is found to be different from that of Gilman or Grignard reagents toward the studied enynes. The resulting cyclopentenofullerenes, characterized with spectrometric methods and single crystal X‐ray diffraction analysis, exhibit comparable or higher LUMO energy levels than a typical n‐type material, [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM).magnified image