Research Aimed for the Development of Transition Metal Catalyzed Heterocyclic Synthesis.

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This research was aimed to develop new synthetic methodologies for nitrogen and oxygen heterocycles by the use of the oxidizing potential of transition metals. The results obtained in these 3 years are summarized as follows.(1) For the palladium(II) catalyzed amination of olefins, urea serves as a specific aminonucleophile (not an oxygen nucleophile) and shows the higher reactivity and versatility as compared with sulfonamide and carbamate, commonly utilized hitherto. Based on this methodology, the following classes of compounds can be synthesized very efficiently; cis 3-hydroxypyrrolidine-2-acetic acid lactones (versatile synthetic intermediates for pyrrolitidine alkaloid), bicyclic dihydrouracil, cyclic urea, gamm- and -amino amino acids. (2)alpha-Methylene-gamma-butyrolactones are synthesized by palladium(II) catalyzed carbonylation of 3-butyn-1-ols. The yields are highly dependent on the kind of bases. Propylene oxide proved to be the best base. (3) 2-Arylheterocycles (e.g., 2-aryltetrahydrofurans, 2-Arylpiperidines) are synthesized by the Pd(II)-catalyzed reaction of homoallyl alcohols and homoallylamines, respectively, with aryltrialkyltin.