Gold-Catalyzed Oxidative Cyclizations of {<i>o</i>-(Alkynyl)phenyl propargyl} Silyl Ether Derivatives Involving 1,2-Enynyl Migration: Synthesis of Functionalized 1<i>H</i>-Isochromenes and 2<i>H</i>-Pyrans
作者:Jidong Zhao、Wei Xu、Xin Xie、Ning Sun、Xiangdong Li、Yuanhong Liu
DOI:10.1021/acs.orglett.8b02380
日期:2018.9.7
A new and convenient strategy for the synthesis of functionalized 1H-isochromene and 2H-pyran derivatives based on gold-catalyzed oxidative cyclizations of o-(alkynyl)phenyl propargyl ether derivatives has been developed. The reaction proceeds via gold-catalyzed highly regioselective oxidation, followed by 1,2-migration of an enynyl group and nucleophlic addition. Isocoumarins were also constructed
Gold-Catalyzed Cyclization of 1,6-Diyne-4-en-3-ols: Stannyl Transfer from 2-Tributylstannylfuran Through Au/Sn Transmetalation
作者:Yifeng Chen、Ming Chen、Yuanhong Liu
DOI:10.1002/anie.201201523
日期:2012.6.18
Gold‐tinted: A gold catalyzed cyclization reaction of 1,6‐diyne‐4‐en‐3‐ols, incorporating an in situ stannyltransfer reaction involving 2‐tributylstannylfuran, gives synthetically valuable 2‐stannylnaphthalenes (see scheme; DCE=dichloroethane). A gem‐diaurated furan complex, was isolated and fully characterized by X‐ray crystallographic analysis, and provides strong evidence for a tin to gold transmetalation
Gold-Catalyzed Cascade Cyclizations of 1,6-Diynyl Carbonates to Benzo[b]fluorenes Involving Arylation of Oxocarbenium Ion Intermediates and Decarboxylative Etherification
作者:Yifeng Chen、Ming Chen、Yuanhong Liu
DOI:10.1002/anie.201201799
日期:2012.6.25
cycloisomerizations give access to highly substituted benzo[b]fluorenes under mild reaction conditions (see scheme). Experimental results indicate that the in situ formed oxocarbeniumionintermediates, derived from gold‐catalyzed 3,3‐rearrangement and 6‐endo‐dig cyclization, undergo intramolecular arylation and subsequent decarboxylativeetherification to furnish the final ether products.
重排:在温和的反应条件下,所描述的金催化的环异构化反应可得到高度取代的苯并[ b ]芴(参见方案)。实验结果表明,在原位形成oxocarbenium离子中间体,衍生自金催化3,3-重排和6-内-挖环化,分子内经历芳基化和随后的脱羧醚化,得到最终的醚产物。