Preparation of 5-Substituted 3-Aminofuran-2-carboxylate Esters

Abstract
An efficient method for the preparation of 3-aminofuran-2-carboxylate esters has been developed. This method is based on the reaction of an α-cyanoketone with ethyl glyoxylate under Mitsunobu conditions to produce a vinyl ether in good yield. Subsequent treatment of the vinyl ether with sodium hydride afforded the 3-aminofuran. It was also found that a one-pot procedure using the Mitsunobu reaction followed by cyclization afforded the 3-aminofuran in comparable yield. Currently, this method is limited to the synthesis of 5-alkyl-, 5-aryl-, and 4,5-fused bicyclic furans.