title: Self-association free bifunctional thiourea organocatalysts: synthesis of chiral α-amino acids via dynamic kinetic resolution of racemic azlactones.
abstract: Concentration-independent high enantioselectivity in the dynamic kinetic resolution (DKR) of racemic azlactones affording chiral α-aminoesters has been achieved using self-association free thiourea-based dimeric cinchona alkaloid organocatalysts. Detailed experimental studies and single crystal X-ray analysis confirmed that these bifunctional organocatalysts I do not form H-bonded self-aggregates in either solution or solid state.
authors.affiliation: Department of Chemistry, Sungkyunkwan University, 300 Cheoncheon, Jangan, Suwon, Gyeonggi 440-746, Korea.
authors.forename: Joong-Suk
authors.initials: JS
authors.lastname: Oh
authors.forename: Ji-Woong
authors.initials: JW
authors.lastname: Lee
authors.forename: Tae Hee
authors.initials: TH
authors.lastname: Ryu
authors.forename: Jae Heon
authors.initials: JH
authors.lastname: Lee
authors.forename: Choong Eui
authors.initials: CE
authors.lastname: Song
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D002930:Cinchona Alkaloids / Q000737:chemistry; D018360:Crystallography, X-Ray; D007700:Kinetics; D007783:Lactones / Q000737:chemistry*; D008958:Models, Molecular; D013237:Stereoisomerism; D013890:Thiourea / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D002930:Cinchona Alkaloids; D007783:Lactones; D013890:Thiourea