title: Versatile Homoallylic Boronates by Chemo-, SN2'-, Diastereo- and Enantioselective Catalytic Sequence of Cu-H Addition to Vinyl-B(pin)/Allylic Substitution.
abstract: A highly chemo-, diastereo- and enantioselective catalytic method that efficiently combines a silyl hydride, vinyl-B(pin) (pin=pinacolato) and (E)-1,2-disubstituted allylic phosphates is introduced. Reactions, best promoted by a Cu-based complex with a chiral sulfonate-containing N-heterocyclic carbene, are broadly applicable. Aryl-, heteroaryl-, alkenyl-, alkynyl- and alkyl-substituted allylic phosphates may thus be converted to the corresponding homoallylic boronates and then alcohols (after C-B bond oxidation) in 46-91 % yield and in up to >98 % SN2':SN2 ratio, 96:4 diastereomeric ratio and 98:2 enantiomeric ratio. The reasons why an NHC-Cu catalyst is uniquely effective (vs. the corresponding phosphine systems) and the basis for different trends in stereoselectivity are provided with the aid of DFT calculations.
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, 02467, USA.
authors.forename: Jaehee
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, 02467, USA.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Torker
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, 02467, USA.
authors.forename: Amir H
authors.initials: AH
authors.lastname: Hoveyda
mesh_terms: D000438:Alcohols / Q000138:chemical synthesis* / Q000737:chemistry; D000498:Allyl Compounds / Q000737:chemistry*; D001897:Boronic Acids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry; D015394:Molecular Structure; D011789:Quantum Theory; D013237:Stereoisomerism
chemical_list: D000438:Alcohols; D000498:Allyl Compounds; D001897:Boronic Acids; D006571:Heterocyclic Compounds; C030011:carbene; D003300:Copper; D006859:Hydrogen; D008697:Methane
keywords: boron; copper; enantioselective catalysis; enantioselective synthesis; multicomponent reactions