title: Enantioselective Synthesis of Dialkylated α-Hydroxy Carboxylic Acids through Asymmetric Phase-Transfer Catalysis.
abstract: In the presence of an L-tert-leucine-derived urea-ammonium salt as phase-transfer catalyst, a highly enantioselective alkylation of 5H-oxazol-4-ones with various benzyl bromides and allylic bromides has been developed to furnish catalytic asymmetric synthesis of biologically important dialkylated α-hydroxy carboxylic acids with a broad scope. This is the first example of an L-amino acid-derived urea-ammonium salt being used as a phase-transfer catalyst with excellent catalytic efficiency.
authors.affiliation: †Key Laboratory of Natural Medicine and Immuno-Engineering of Henan Province, Henan University, Kaifeng, Henan 475004, P. R. China.
authors.forename: Shaobo
authors.initials: S
authors.lastname: Duan
authors.affiliation: †Key Laboratory of Natural Medicine and Immuno-Engineering of Henan Province, Henan University, Kaifeng, Henan 475004, P. R. China.
authors.forename: Sanliang
authors.initials: S
authors.lastname: Li
authors.affiliation: ‡Division of Chemistry and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link 637371, Singapore.
authors.forename: Xinyi
authors.initials: X
authors.lastname: Ye
authors.affiliation: †Key Laboratory of Natural Medicine and Immuno-Engineering of Henan Province, Henan University, Kaifeng, Henan 475004, P. R. China.
authors.forename: Nuan-Nuan
authors.initials: NN
authors.lastname: Du
authors.affiliation: †Key Laboratory of Natural Medicine and Immuno-Engineering of Henan Province, Henan University, Kaifeng, Henan 475004, P. R. China.|‡Division of Chemistry and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link 637371, Singapore.
authors.forename: Choon-Hong
authors.initials: CH
authors.lastname: Tan
authors.affiliation: †Key Laboratory of Natural Medicine and Immuno-Engineering of Henan Province, Henan University, Kaifeng, Henan 475004, P. R. China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Jiang
mesh_terms: D000478:Alkylation; D064751:Ammonium Compounds / Q000737:chemistry*; D002264:Carboxylic Acids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D007930:Leucine / Q000737:chemistry*; D015394:Molecular Structure; D010080:Oxazoles / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D064751:Ammonium Compounds; D002264:Carboxylic Acids; D010080:Oxazoles; D007930:Leucine