title: Regio- and stereoselective monoepoxidation of dienes using methyltrioxorhenium: synthesis of allylic epoxides.
abstract: Methyltrioxorhenium (MTO) complexed with pyridine was shown to be a highly effective catalyst for the regioselective monoepoxidation of conjugated di- and trienes using 30% H2O2 at or below room temperature. The resultant allylic epoxides, and the triols derived from them, are versatile synthetic intermediates as well as substructures present in many bioactive natural products. The site of epoxidation was dependent upon olefin substitution, olefin geometry (Z vs E), and the presence of electron-withdrawing substituents on adjacent carbons. For 1-acyl(silyl)oxypenta-2,4-dienes, epoxidation of the distal olefin was generally favored in contrast to the adjacent regioselectivity characteristic of Sharpless, peracid, and other directed epoxidations of hydroxylated dienes.
authors.affiliation: Division of Chemistry, Department of Biochemistry, University of Texas Southwestern Medical Center , Dallas, Texas 75390, United States.
authors.forename: Saroj Ranjan
authors.initials: SR
authors.lastname: De
authors.forename: Ganesh
authors.initials: G
authors.lastname: Kumar
authors.forename: Jawahar L
authors.initials: JL
authors.lastname: Jat
authors.forename: Saritha
authors.initials: S
authors.lastname: Birudaraju
authors.forename: Biao
authors.initials: B
authors.lastname: Lu
authors.forename: Rajkumar
authors.initials: R
authors.lastname: Manne
authors.forename: Narender
authors.initials: N
authors.lastname: Puli
authors.forename: Adeniyi Michael
authors.initials: AM
authors.lastname: Adebesin
authors.forename: John R
authors.initials: JR
authors.lastname: Falck
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D004852:Epoxy Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D004852:Epoxy Compounds; D009942:Organometallic Compounds; C411866:methyltrioxorhenium VII; D006861:Hydrogen Peroxide