An efficient approach for monofluorination via aqueous fluorolactonization reaction of 2,3-allenoic acids with Selectfluor

[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.