Direct Synthesis of 4-Fluoroisoxazoles through Gold-Catalyzed Cascade Cyclization–Fluorination of 2-Alkynone O-Methyl Oximes
摘要:
A tandem protocol for the synthesis of fluorinated isoxazoles has been developed via catalytic intramolecular cyclizations of 2-alkynone O-methyl mimes and ensuing fluorination. The reactions proceed smoothly at room temperature in the presence of 5 mol % of (IPr)AuCl, 5 mol % of AgOTs, 2.5 equiv of Selectfluor, and 2 equiv of NaHCO3. This process features an efficient one-pot cascade route to fluoroisoxazoles with high yields and high selectivity under mild reaction conditions.
Trimethylsilyl Trifluoromethanesulfonate- Accelerated Addition of Catalytically Generated Zinc Acetylides to Aldehydes
摘要:
In the presence of TMSOTf, a wide variety of terminal acetylenes add rapidly and efficiently to aldehydes via a catalytically generated zinc acetylide. In the absence of TMSOTf, no reaction is observed under otherwise identical conditions.
Trimethylsilyl Trifluoromethanesulfonate- Accelerated Addition of Catalytically Generated Zinc Acetylides to Aldehydes
作者:C. Wade Downey、Brian D. Mahoney、Vincent R. Lipari
DOI:10.1021/jo900102w
日期:2009.4.3
In the presence of TMSOTf, a wide variety of terminal acetylenes add rapidly and efficiently to aldehydes via a catalytically generated zinc acetylide. In the absence of TMSOTf, no reaction is observed under otherwise identical conditions.
Direct Synthesis of 4-Fluoroisoxazoles through Gold-Catalyzed Cascade Cyclization–Fluorination of 2-Alkynone <i>O</i>-Methyl Oximes
A tandem protocol for the synthesis of fluorinated isoxazoles has been developed via catalytic intramolecular cyclizations of 2-alkynone O-methyl mimes and ensuing fluorination. The reactions proceed smoothly at room temperature in the presence of 5 mol % of (IPr)AuCl, 5 mol % of AgOTs, 2.5 equiv of Selectfluor, and 2 equiv of NaHCO3. This process features an efficient one-pot cascade route to fluoroisoxazoles with high yields and high selectivity under mild reaction conditions.