Direct Synthesis of 4-Fluoroisoxazoles through Gold-Catalyzed Cascade Cyclization-Fluorination of 2-Alkynone O-Methyl Oximes
Yunkyung Jeong, Bom-I Kim, Jae Kyun Lee and Jae-Sang Ryu*
*College of Pharmacy & Graduate School of Pharmaceutical Sciences, Ewha Womans University, 11-1 Daehyun-Dong, Seodaemun-Gu, Seoul 120-750, Republic of Korea, Email: ryujewha.ac.kr
Y. Jeong, B.-I Kim, J. K. Lee, J.-S. Ryu, J. Org. Chem., 2014, 79, 6444-6455.
A catalytic intramolecular cyclization of 2-alkynone O-methyl oximes and subsequent fluorination proceeds 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.
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