Gold-Catalyzed Oxidations of 1,3-Diynamides with C(1) versus C(3) Regioselectivity: Catalyst-Dependent Oxidative
Manisha Skaria1, Yu-Chen Hsu1, Yan-Ting Jiang1
1Frontier Research Center on Fundamental and Applied Science of Matters, Department of Chemistry, National Tsing-Hua University, Kuang-Fu Road, Hsinchu 30013, Taiwan, ROC.
Abstract:
This work reports two distinct paths in catalytic oxidations of 1,3-diynamides with 8-methylquinoline oxide. A typical C(1) regioselectivity was observed for aryl-substituted 1,3-diyn-1-amides, whereas an unexpected C(3) regioselectivty occurred for 5-hydroxy1,3-diyn-1-amides. We focused on the C(3) oxidations of 5-hydroxy1,3-diyn-1-amides because we observed two oxidative cyclizations of the same substrates to yield 2-aminomethylenefuran-3(2H)-ones and 2-amino-4H-pyran-4-ones using AuCl3 and a cationic gold catalyst, respectively. Density functional theory calculations were performed to rationalize the C(3) regioselectivity on 5-hydroxy1,3-diyn-1-amides.
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