Synthesis of Enol Lactones via Cu(I)-Catalyzed Intramolecular O-Vinylation of Carboxylic Acids
作者:Changhui Sun、Yewen Fang、Shuang Li、Yue Zhang、Qiwu Zhao、Shana Zhu、Chaozhong Li
DOI:10.1021/ol9015578
日期:2009.9.17
catalysis of CuI/trans-N,N′-dimethylcyclohexane-1,2-diamine, a number of carboxylic acids underwent efficient intramolecular O-vinylation with vinyl bromides leading to the synthesis of the corresponding five- and six-membered enollactones. The same catalytic system also led to the efficient cycloisomerization of alkynoic acids.
Cycloisomerization versus Hydration Reactions in Aqueous Media: A Au(III)-NHC Catalyst That Makes the Difference
作者:Eder Tomás-Mendivil、Patrick Y. Toullec、Josefina Díez、Salvador Conejero、Véronique Michelet、Victorio Cadierno
DOI:10.1021/ol300811e
日期:2012.5.18
A novel water-soluble Au(III)-NHC complex has been synthesized and successfully applied in the intramolecular cyclization of gamma-alkynoic acids into enol-lactones under biphasic toluene/water conditions, thus representing a rare example of an active and selective catalyst for this transformation In aqueous media. Remarkably, competing alkyne hydration processes were not observed, even during the desymmetrization reaction of challenging 1,6-diyne substrates. In addition, after phase separation, the water-soluble Au(III) catalyst could be recycled 10 times without loss of activity or selectivity.