Palladium-Catalyzed Synthesis Of 2-Aminofurans

In this dissertation, a couple of Pd-catalyzed cycloisomerization of homoallenyl amides reactions have been developed, giving a variety of 2-aminofurans in promising yields under very mild reaction conditions, which consist of three parts:Firstly, a Pd-catalyzed divergent cyclization, including cycloisomerization and aerobic oxidative cycloisomerization of homoallenyl amides has been realized. Varieties of functionalized 2-amino-5-alkylfurans and 2-amino-5-formylfurans can be selectively synthesized in good to excellent yields. Preliminary mechanistic studies show that peroxide may be a key intermediate for this Pd-catalyzed radical aerobic oxidative cycloisomerization of homoallenyl amides.Secondly, a fine-tunable transformation, including Pd-catalyzed acetoxylative, alkoxylative, and hydroxylative cycloisomerization of homoallenyl amides, has been developed with hypervalent iodines as oxidants, giving polysubstituted 2-aminofurans in promising yields at room temperature.Finally, a very mild, Pd-catalyzed azidative cycloisomerization of homoallenyl amides is described, giving rise to 2-amino-5-azidomethylfurans in good to excellent yields. The resulting products can be smoothly converted into 1.2.3-triazoles via the so-called Click reaction.