One-Pot Synthesis of Benzene-Fused Medium-Ring Ketones: Gold Catalysis-Enabled Enolate Umpolung Reactivity
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- 作者：Zhou Xu ; Hongyi Chen ; Zhixun Wang ; Anguo Ying ; Liming Zhang
- 刊名：Journal of the American Chemical Society
- 出版年：2016
- 出版时间：May 4, 2016
- 年：2016
- 卷：138
- 期：17
- 页码：5515-5518
- 全文大小：377K
- 年卷期：0
- ISSN：1520-5126
文摘
Enolate umpolung reactivities offer valuable and potentially unique alternatives over the enolate counterparts for the construction of ubiquitous carbonyl compounds. We disclose here that N-alkenoxypyridinium salts, generated readily upon gold-catalyzed additions of protonated pyridine N-oxide to C–C triple bonds of unactivated terminal alkynes, display versatile enolate umpolung chemistry upon heating and react with tethered arene nucleophiles in an SN2′ manner. In a synthetically efficient one-pot, two-step process, this chemistry enables expedient preparation of valuable benzo-fused seven-/eight-membered cyclic ketones, including those of O-/N-heterocycles, from easily accessible aryl-substituted linear alkyne substrates. The reaction yields can be up to 87%.