Study on the selectivity in the electrophilic monofluorination of 2,3-allenoates with Selectfluor™: an efficient synthesis of 4-fluoro-2(5H)-furanones and 3-fluoro-4-oxo-2(E)-alkenoates
An Efficient Approach for Monofluorination via Aqueous Fluorolactonization Reaction of 2,3-Allenoic Acids with Selectfluor
作者:Chao Zhou、Zhichao Ma、Zhenhua Gu、Chunling Fu、Shengming Ma
DOI:10.1021/jo702409y
日期:2008.1.1
[GRAPHICS]We have developed a convenient method for the efficient monofluorination via the electrophilic fluorocyclization reaction of 2,3-allenoic acids with Selectfluor in MeCN in the presence of 10 equiv of H2O or even in pure water to afford beta-fluorobutenolides in moderate to high yields.
Study on the selectivity in the electrophilic monofluorination of 2,3-allenoates with Selectfluor™: an efficient synthesis of 4-fluoro-2(5H)-furanones and 3-fluoro-4-oxo-2(E)-alkenoates
作者:Bo Lü、Chunling Fu、Shengming Ma
DOI:10.1039/b917793k
日期:——
Different from the reaction of 2,3-allenoic acids with Selectfluorâ¢, 4-fluoro-2(5H)-furanones and (E)-3-fluoro-4-oxo-2-alkenoates were highly selectively generated from 2,4-disubstituted 2,3-allenoates with Selectfluor⢠under different conditions in moderate yields. The reaction of 2,4,4-trisubstituted 2,3-allenoates afforded the corresponding 4-fluoro-2(5H)-furanones highly selectively with up to 95% yield under different conditions. The scope of the substrates has been carefully explored. Due to the more readily availability of 2,3-allenoates as compared to 2,3-allenoic acids, new 4-fluoro-2(5H)-furanones were prepared. Based on the isolation and characterization of the minor fluorohydroxylation product E-5m, a mechanism has been proposed.