An Efficient [2 + 2 + 1] Synthesis of 2,5-Disubstituted Oxazoles via Gold-Catalyzed Intermolecular Alkyne Oxidation

Citations Over TimeTop 1% of 2011 papers

Abstract

The first efficient intermolecular reaction of gold carbene intermediates generated via gold-catalyzed alkyne oxidation has been realized using nitriles as both the reacting partner and the reaction solvent, offering a generally efficient synthesis of 2,5-disubstituted oxazoles with broad substrate scope. The overall reaction is a [2 + 2 + 1] annulation of a terminal alkyne, a nitrile, and an oxygen atom from an oxidant. The reaction conditions are exceptionally mild, and a range of functional groups are easily tolerated. With complex and/or expensive nitriles, only 3 equiv could be sufficient to achieve serviceable yields in the absence of any solvent and using only 1 mol % BrettPhosAuNTf(2) as the catalyst.

Related Papers

• → Synthesis of 3,4-disubstituted cinnolines by the Pd-catalyzed annulation of 2-iodophenyltriazenes with an internal alkyne(2011)39 cited
• → Synthesis of Natural Products, Carbocycles, and Heterocycles by Hauser–Kraus Annulation(2023)13 cited
• → Divergent Synthesis of Oxepino-Phthalides and [5,5]-Oxaspirolactones through [2 + 2 + 2]- and [2 + 3]-Annulation of Alkynyl Alcohols with α-Ynone-Esters(2023)3 cited
• → [4 + 2] Annulation of Activated o-Toluate/o-Tolualdehyde Donors (Hauser-Leusen Annulation)(2018)1 cited
• → [4 + 2] Annulation With Nonactivated o-Toluate Donors (Staunton-Weinreb-Myers Annulation)(2018)