5-Endo-dig electrophilic cyclization of 1,4-disubstituted but-3-yn-1-ones: regiocontrolled synthesis of 2,5-disubstituted 3-bromo- and 3-iodofurans

Abstract

[reaction: see text] 5-Endo-dig electrophilic cyclization of 1,4-diaryl but-3-yn-1-ones with N-bromosuccinimide or N-iodosuccinimide/acetone and iodine monochloride/CH(2)Cl(2), at room temperature, in the absence of base, provides 3-halo-2,5-diarylfurans with excellent regiocontrol and high yields (81-94%).