4. Conclusions A simple and efficient approach to the synthesis of (purin-6-yl)alanines based on Negishi cross-coupling reactions of 6-iodopurines and iodozinc- alanines applicable to the synthesis of both racemic and optically pure compounds was developed. Though analogous reactions were used before for the synthesis of some simple aryl- or hetarylaranines, this was the first successful use in the functionalization ofprotected nucleobases and nucleosides. A practical method for synthesis of enantiomerically pure (purin-6_ yl)phenylalanines by palladium catalyzeď, copper mediated Stille cross-coupling reactions ofprotected 4-(trimethylstanyl)phenylalanines and 6-iodopurines was developed. This method was used in the synthesis of series of (purin_6_ yl)phenylalanines (bases and nucleosides) varying in substitution in position 9 of purine scaffold and in absolute configuration on o-carbon ofphenylalanine. The shaughnessy method for the Suzuki cross-coupling reactions in aqueous media was further optimized and applied to the single-step synthesis of novel optically pure (adenin-8-yl)phenylalanines and (purine_6_yl)phenyl_ alanines. wide tolerance of this methodology towards variety of functionalities and its applicability to 1abile systems was demonstrated particularly by the very first examples of couplings...4. Conclusions A simple and efficient approach to the synthesis of (purin-6-yl)alanines based on Negishi cross-coupling reactions of 6-iodopurines and iodozinc- alanines applicable to the synthesis of both racemic and optically pure compounds was developed. Though analogous reactions were used before for the synthesis of some simple aryl- or hetarylaranines, this was the first successful use in the functionalization ofprotected nucleobases and nucleosides. A practical method for synthesis of enantiomerically pure (purin-6_ yl)phenylalanines by palladium catalyzeď, copper mediated Stille cross-coupling reactions ofprotected 4-(trimethylstanyl)phenylalanines and 6-iodopurines was developed. This method was used in the synthesis of series of (purin_6_ yl)phenylalanines (bases and nucleosides) varying in substitution in position 9 of purine scaffold and in absolute configuration on o-carbon ofphenylalanine. The shaughnessy method for the Suzuki cross-coupling reactions in aqueous media was further optimized and applied to the single-step synthesis of novel optically pure (adenin-8-yl)phenylalanines and (purine_6_yl)phenyl_ alanines. wide tolerance of this methodology towards variety of functionalities and its applicability to 1abile systems was demonstrated particularly by the very first examples of couplings...Katedra organické chemieDepartment of Organic ChemistryFaculty of SciencePřírodovědecká fakult