Syntheses of 4H-Thiopyran-4-one 1,1-Dioxides as Precursors to Sulfone-Containing Analogs of Tetracyanoquinodimethane
摘要:
Synthetic routes to the unsubstituted 4H-thiopyran-4-one 1,1-dioxide (5a), 2,6-dialkyl-substituted, 2-aryl- or 2-heteroaryl-6-alkyl-substituted, 2,6-diaryl- or diheteroaryl-substituted, and 2-heteroaryl-6-aryl-substituted 4H-thiopyran-4-one 1,1-dioxides 5b-s are described. Sodium hydrosulfide hydrate in buffered aqueous alcohol can be used as a substitute for hydrogen sulfide gas for the introduction of sulfur to methyl acrylate, to 1,5-disubstituted-1,4-pentadien-3-ones 13, or to 1,5-disubstituted-1,4-pentadiyn-3-ones 17. The double dehydrogenation af 2,3,5,6-tetrahydrothiopyran-4-one 1,1-dioxides 13 with iodine-DMSO-sulfuric acid gives thiopyran-4-one 1,1-dioxides 5 in good yield and small amounts of 1,4-pentadien-3-ones 13. 2,3,5,6-Tetrahydrothiopyran-4-one 1,1-dioxide (9) and 5,6-dihydrothiopyran-4-one 1,1-dioxide (12), which lack aryl or heteroaryl substituents, give poor yields of 4H-thiopyran-4-one 1,1-dioxide (5a) with iodine-DMSO-sulfuric acid.
Gold-Catalyzed Hydrophenoxylation of Propargylic Alcohols and Amines: Synthesis of Phenyl Enol Ethers
作者:Victor Laserna、Catherine Jeapes Rojas、Tom D. Sheppard
DOI:10.1021/acs.orglett.9b01208
日期:2019.6.21
A practical method for the synthesis of phenyl enol ethers is reported. The combination of a gold(I) catalyst and potassium carbonate selectively mediates the addition of phenols to propargylic alcohols/amines in a chemo-, regio-, and stereoselective fashion in high yield. The resulting enol ethers are formed exclusively with a Z-configuration and can be obtained from a wide array of phenols and propargylic
Synthesis of Highly Substituted 3-Formylfurans by a Gold(I)-Catalyzed Oxidation/1,2-Alkynyl Migration/Cyclization Cascade
作者:Tao Wang、Shuai Shi、Max M. Hansmann、Eva Rettenmeier、Matthias Rudolph、A. Stephen K. Hashmi
DOI:10.1002/anie.201310146
日期:2014.4.1
3‐Formylfuran derivatives are core structures of a variety of bioactive natural products. However, procedures for their preparation are still rare and generally inefficient in terms of atom economy: These methods require multiple steps or harsh reaction conditions and show selectivity problems. An efficient gold(I)‐catalyzed cascade reaction that leads to 3‐formylfurans from easily accessible starting
Recyclable gold(I)-catalyzed oxidative cyclization of 1,4-diyn-3-ols leading to highly substituted 3-formylfurans
作者:Xiaoqiang Xiao、Siqi Liu、Mingzhong Cai
DOI:10.1016/j.jorganchem.2022.122527
日期:2022.12
An efficient heterogeneous gold(I)-catalyzed cascade oxidation/1,2-alkynyl migration/cyclization reaction of 1,4-diyn-3-ols has been developed. The reaction proceeds effectively in toluene at room temperature by using 3 mol% of MCM-41-anchored sterically demanding NHC-gold(I) complex [MCM-41-IPrAuOTf] as catalyst and 3,5-dichloropyridine N-oxide as oxidant and offers a general and practical route for
concise and efficientsynthesis of fully substituted cyclobutane derivatives from 1,4-diyn-3-ols and anhydrides was developed. Mechanistic studies indicated that a tandem esterification, isomerization to give allenyl ester, and homointermolecular [2+2] cycloaddition might be involved. The features of this protocol are its operational practicality, mild reaction conditions, and highregio- and stereoselectivity
Gold-Catalyzed [4 + 1]-Annulation Reactions between 1,4-Diyn-3-ols and Isoxazoles To Construct a Pyrrole Core
作者:Rahul Dadabhau Kardile、Balaji S. Kale、Pankaj Sharma、Rai-Shung Liu
DOI:10.1021/acs.orglett.8b01398
日期:2018.7.6
This work reports gold-catalyzed [4 + 1]-annulation reactions between 1,4-diyn-3-ols and isoxazoles or benzisoxazoles to yield pyrrole derivatives. The reaction chemoselectivity is controlled by an initial attack of an isoxazole at a less hindered alkyne to form gold carbenes, further inducing a 1,2-migration of a second alkyne group. A broad substrate scope of 1,4-diyn-3-ols, isoxazoles and even benzisoxazoles highlighted the reaction utility.