From Propargylic Amides to Functionalized Oxazoles: Domino Gold Catalysis/Oxidation by Dioxygen
作者:A. Stephen K. Hashmi、Maria Camila Blanco Jaimes、Andreas M. Schuster、Frank Rominger
DOI:10.1021/jo301288w
日期:2012.8.3
5-disubstituted oxazoles from propargylic amides is reported. A series of propargylic amides were transformed to the corresponding alkylideneoxazolines by a gold(I) catalyst. The next step was an autoxidation to hydroperoxides bearing the heteroaromatic oxazoles. Experiments addressing the reaction mechanism reveal a radical pathway for this autoxidation process. The hydroperoxides could conveniently be converted
approach for the bromide-mediated selenocyclization of N-propargylamides with diselenides is described, providing a synthetic route for the synthesis of various seleno-oxazoles in 41–73% yields. The success of gram-scale experiments demonstrate the potential value of this protocol in synthetic chemistry. Mechanistic investigations suggest that this selenocyclization protocol proceed through two possible
Sequential Au/Cu Catalysis: A Two Catalyst One-Pot Protocol for the Enantioselective Synthesis of Oxazole α-Hydroxy Esters <i>via</i>
Intramolecular Cyclization/Intermolecular Alder-Ene Reaction
作者:Kumara Swamy Nalivela、Matthias Rudolph、Elham S. Baeissa、Basma G. Alhogbi、Ibraheem A. I. Mkhalid、A. Stephen K. Hashmi
DOI:10.1002/adsc.201800246
日期:2018.6.5
alkylglyoxylates 3 was developed. The first step of the one‐pot procedure is the selective intramolecular in situ formation of an alkylideneoxazoline 2, which then in an intermolecular reaction is enantioselectively transformed to the oxazole α‐hydroxy ester derivatives 4 in quantitative yield and good to excellent enantioselectivity via an asymmetric copper(II)‐catalyzed Alder‐enereaction.