Gold- and Silver-Catalyzed Reactions of Propargylic Alcohols in the Presence of Protic Additives
作者:Matthew N. Pennell、Peter G. Turner、Tom D. Sheppard
DOI:10.1002/chem.201102830
日期:2012.4.10
secondary and tertiary propargylicalcohols undergo a Meyer–Schusterrearrangement to give enones at room temperature in the presence of a gold(I) catalyst and small quantities of MeOH or 4‐methoxyphenylboronic acid. The syntheses of the enone natural products isoegomaketone and daphenone were achieved using this reaction as the key step. The rearrangement of primary propargylicalcohols can readily be combined
Regioselective Dihalohydration Reactions of Propargylic Alcohols: Gold-Catalyzed and Noncatalyzed Reactions
作者:Jarryl M. D'Oyley、Abil E. Aliev、Tom D. Sheppard
DOI:10.1002/anie.201405348
日期:2014.9.26
The regioselective conversion of propargylicalcohols into previously unreported α,α‐diiodo‐β‐hydroxyketones was achieved by treatment with N‐iodosuccinimide in the presence of a gold catalyst. The corresponding α,α‐dichloro‐β‐hydroxyketones were obtained by treatment with trichloroisocyanuric acid in the absence of a catalyst. The latter reaction can be extended to other alkynols. These transformations
Dihalohydration of Alkynols: A Versatile Approach to Diverse Halogenated Molecules
作者:Samantha M. Gibson、Jarryl M. D'Oyley、Joe I. Higham、Kate Sanders、Victor Laserna、Abil E. Aliev、Tom D. Sheppard
DOI:10.1002/ejoc.201800668
日期:2018.8.7
reactions of propargylic alcohols can be used to access a wide variety of useful halogenated building blocks. A novel procedure for dibromohydration of alkynes has been developed, and a selection of dichloro and dibromo diols and cyclic ethers were synthesized. The dihalohydration of homo‐propargylic alcohols provides a usefulroute to 3‐halofurans, which were shown to readily undergo cycloaddition reactions
A Microwave-Assisted Domino Rearrangement of Propargyl Vinyl Ethers to Multifunctionalized Aromatic Platforms
作者:David Tejedor、Gabriela Méndez-Abt、Leandro Cotos、Miguel A. Ramirez、Fernando García-Tellado
DOI:10.1002/chem.201003532
日期:2011.3.14
H makes a difference! A novel reactivity profile of propargyl vinyl ethers has been developed, which is controlled by the presence of a hydrogen atom at the homopropargylic position (see scheme; EWG=electron‐withdrawing group). This strategy was conveniently used to construct multifunctionalized phenolic platforms, including salicylaldehydes and the corresponding ketone derivatives.
Copper-catalyzed skeletal rearrangement of O-propargylic aryloximes (E)-1 were carried out to afford the corresponding four-membered cyclic nitrones 2 in good to excellent yields. The optimal reactions conditions of the highly regioselective reactions involved the use of [CuCl(cod)](2) in acetonitrile at 70 degrees C. In the case of (Z)-1, however, the reaction proceeded in the absence of the copper catalysts to afford the identical compound 2 in good yields. Furthermore, the reactions were also carried out using chiral substrates (R)-1 in the presence of Cu catalysts to afford (R)-2 with good levels of chirality transfer.