title: Enantioselective Alkylation of Amino Acid Derivatives Promoted by Cyclic Peptoids under Phase-Transfer Conditions.
abstract: The effects of substituents and cavity size on catalytic efficiency of proline-rich cyclopeptoids under phase-transfer conditions were studied. High affinity constants (Ka) for the sodium and potassium cations, comparable to those reported for crown ethers, were observed for an alternated N-benzylglycine/L-proline hexameric cyclopeptoid. This compound was found to catalyze the alkylation of N-(diphenylmethylene)glycine cumyl ester in values of enantioselectivities comparable with those reported for the Cinchona alkaloid ammonium salts derivatives (83-96% ee), and with lower catalyst loading (1-2.5% mol), in the presence of a broad range of benzyl, allyl and alkyl halides.
authors.affiliation: Dipartimento di Chimica e Biologia "A. Zambelli", Università degli Studi di Salerno , Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
authors.forename: Rosaria
authors.initials: R
authors.lastname: Schettini
authors.affiliation: Dipartimento di Chimica e Biologia "A. Zambelli", Università degli Studi di Salerno , Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: De Riccardis
authors.affiliation: Dipartimento di Chimica e Biologia "A. Zambelli", Università degli Studi di Salerno , Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Della Sala
authors.affiliation: Dipartimento di Chimica e Biologia "A. Zambelli", Università degli Studi di Salerno , Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Izzo
mesh_terms: D000478:Alkylation; D001120:Arginine / Q000737:chemistry*; D001555:Benzene Derivatives / Q000737:chemistry*; D002930:Cinchona Alkaloids / Q000737:chemistry*; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000737:chemistry*; D011392:Proline / Q000031:analogs & derivatives / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001555:Benzene Derivatives; D002930:Cinchona Alkaloids; C000610869:N-(diphenylmethylene)glycine cumyl ester; D010456:Peptides, Cyclic; D001120:Arginine; D011392:Proline; C423606:N-benzylglycine; D005998:Glycine