Furan ring as a surrogate for carboxy group (microreview)

Oxidative degradation of furans to corresponding carboxylic acids(1) is a valuable tool in organic synthesis, which provides additional synthetic opportunities in comparison to established methods like nitrile chemistry, organometallic carboxylation, transition metal-catalyzed carbonylation. The proposed approach is applicable to almost every type of furan ring-containing organic substances (steroids, carbohydrates, amino acids and peptides, aromatic and heteroaromatic compounds). It is particularly attractive because of the mild conditions and cheap reagents it needs (cat. RuCl3/NaIO4 or O-3) and also because it tolerates many functional groups. Another advantage is the availability of starting furan derivatives which can be prepared via the Michael addition, alkylation, Mannich reaction, cycloaddition, cross coupling, and many other methods. Here, a short summary is provided of several selected recently published applications of the method in the field of naturally occuring and chiral compounds.