10.1021/jo026757l
The study presents three novel methods for the synthesis of 2-amido substituted furans, which are valuable intermediates in the synthesis of various natural products and alkaloids. The first method involves the thermolysis of furan-2-carbonyl azide, leading to a Curtius rearrangement and the formation of a furanyl isocyanate intermediate, which is then trapped with different organometallic reagents. The second method is a C-N cross-coupling reaction of bromo-substituted furans with amides, carbamates, and lactams, catalyzed by CuI, yielding 2- and 3-substituted amidofurans in high yields. The third method involves the reaction of cyclic carbinol amides with triflic anhydride to produce R-(trifluoromethyl)sulfonamido-substituted furans under mild conditions. These methods serve to provide diverse and efficient pathways to synthesize 2-amido substituted furans, expanding the synthetic toolkit for the preparation of complex oxygenated polycyclic compounds and potentially facilitating the synthesis of alkaloids.