title: Chiral epoxides via borane reduction of 2-haloketones catalyzed by spiroborate ester: application to the synthesis of optically pure 1,2-hydroxy ethers and 1,2-azido alcohols.
abstract: An enantioselective borane-mediated reduction of a variety of 2-haloketones with 10% spiroaminoborate ester 1 as catalyst is described. By a simple basic workup of 2-halohydrins, optically active epoxides are obtained in high yield and with excellent enantiopurity (up to 99% ee). Ring-opening of oxiranes with phenoxides or sodium azide is investigated under different reaction conditions affording nonracemic 1,2-hydroxy ethers and 1,2-azido alcohols with excellent enantioselectivity (99% ee) and in good to high chemical yield.
authors.affiliation: Department of Chemistry, University of Puerto Rico-H-umacao, CUH Station, Humacao, Puerto Rico 00791.
authors.forename: Kun
authors.initials: K
authors.lastname: Huang
authors.forename: Haiyang
authors.initials: H
authors.lastname: Wang
authors.forename: Viatcheslav
authors.initials: V
authors.lastname: Stepanenko
authors.forename: Melvin
authors.initials: M
authors.lastname: De Jesús
authors.forename: Carilyn
authors.initials: C
authors.lastname: Torruellas
authors.forename: Wildeliz
authors.initials: W
authors.lastname: Correa
authors.forename: Margarita
authors.initials: M
authors.lastname: Ortiz-Marciales
mesh_terms: D000438:Alcohols / Q000138:chemical synthesis* / Q000737:chemistry; D001880:Boranes / Q000737:chemistry*; D002384:Catalysis; D004852:Epoxy Compounds / Q000737:chemistry*; D004952:Esters; D004987:Ethers / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D055620:Optical Phenomena; D010084:Oxidation-Reduction; D013141:Spiro Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D000438:Alcohols; D001880:Boranes; D004852:Epoxy Compounds; D004952:Esters; D004987:Ethers; D007659:Ketones; D013141:Spiro Compounds