报道了钯催化的分子内α-芳基化和脱氟芳构化策略,用于合成多取代的2-萘酚。该方法以邻溴苄基取代的α-氟酮为底物,并以乙酸钯/三苯膦为催化剂,具有良好的官能团耐受性,易于获得的催化剂和起始原料以及高收率的特点。该策略的应用通过合成有用的结构单元(例如,石脑油[2,3- b ]呋喃,萘酚AS-D和配体/催化剂)得到证明。
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
A palladium(0)-catalyzed ring-opening cross-coupling reaction between tert -cyclobutenols and arylhalides produces γ-arylated β,γ-unsaturated ketones. In the case of arylhalides bearing functional groups at the ortho position, the resulting ring-opened ketones undergo intramolecular condensation to afford bicyclic aromatic compounds.
Direct Synthesis of Substituted Naphthalenes from 1,3-Dicarbonyl Compounds and 1,2-Bis(halomethyl)benzenes Including a Novel Rearrangement Aromatization of Benzo[<i>c</i>]oxepine
unexpected rearrangement aromatization of benzo[c]oxepine has been revealed to synthesize substituted naphthalenes. This observation was further exploited to develop an efficient approach for the construction of naphthalenes from simple and commercially available 1,3-dicarbonylcompounds and 1,2-bis(halomethyl)benzene compounds via a new domino reaction sequence.
苯并[ c ]氧杂环丁烷的意外重整芳构化已表明可以合成取代的萘。进一步利用这一观察结果,开发了一种有效的方法,可通过简单的和可商购的1,3-二羰基化合物和1,2-双(卤甲基)苯化合物通过新的多米诺反应序列来构建萘。
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。
作者:Tuong Anh To、Chao Pei、Rene M. Koenigs、Thanh Vinh Nguyen
DOI:10.1002/anie.202117366
日期:2022.3.21
H-bonding network: Hexafluoroisopropanol (HFIP) can act as a hydrogen-bond donor to enhance the catalytic efficiency of simple Brønsted acid catalysts in carbonyl-olefin metathesis reactions by stabilization of all transition states and intermediates along the reaction pathway.