title: Regio- and enantioselective catalytic monoepoxidation of conjugated dienes: synthesis of chiral allylic cis-epoxides.
abstract: Ti(IV)-salan 4 catalyzes the diastereo- and enantioselective monoepoxidation of conjugated dienes using 30% H2O2 at rt or below even in the presence of other olefins and adjacent stereocenters. Its enantiomer, ent-4, provides access to the opposite diastereomer or enantiomer. The resultant chiral allylic epoxides, and the triols derived from them, are versatile synthetic intermediates as well as substructures present in many bioactive natural products. The epoxidation is highly specific for Z-olefins. For 1-acyl(silyl)oxypenta-2,4-dienes, epoxidation of the distal olefin is generally favored in contrast to the adjacent regioselectivity characteristic of Sharpless, peracid, and other directed epoxidations of hydroxylated dienes.
authors: Division of Chemistry, Department of Biochemistry, University of Texas Southwestern Medical Center , Dallas, Texas 75390, United States.
authors: Jawahar L
authors: JL
authors: Jat
authors: Saroj Ranjan
authors: SR
authors: De
authors: Ganesh
authors: G
authors: Kumar
authors: Adeniyi Michael
authors: AM
authors: Adebesin
authors: Shyam K
authors: SK
authors: Gandham
authors: John R
authors: JR
authors: Falck
mesh_terms: D000466:Alkadienes / Q000138:chemical synthesis / Q000737:chemistry*; D001688:Biological Products / Q000737:chemistry; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D004852:Epoxy Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000466:Alkadienes; D001688:Biological Products; D004852:Epoxy Compounds; D006861:Hydrogen Peroxide