The synthesis of trisubstituted pyrrolidines and tetrahydrofurans from boronic acids, allenes, and imines or aldehydes via a five- and a three-step protocol, respectively, is described. The assignment of the relative stereochemistry in the pyrrolidines and tetrahydrofurans confirmed the mechanistically significant stereochemical divergence of the palladium-catalyzed three-component coupling reaction. The methodology is applicable to the preparation of combinatorial libraries of pyrrolidines related to pharmaceutical agents and bioactive natural products.
Key words
stereoselective synthesis - heterocycles - palladium - multicomponent reactions - ring closure