title: Catalytic enantioselective protoboration of disubstituted allenes. Access to alkenylboron compounds in high enantiomeric purity.
abstract: Proto-boryl additions to 1,1-disubstituted allenes in the presence of 1.0-5.0 mol % of chiral NHC-Cu complexes, B2(pin)2, and t-BuOH proceed to afford alkenyl-B(pin) products in up to 98% yield, >98:2 site selectivity, and 98:2 er. The enantiomerically enriched alkenylboron products can be converted to otherwise difficult-to-access alkenyl bromides, methyl ketones or carboxylic acids. What's more, the corresponding boronic acids may be used in highly stereoselective NHC-Cu-catalyzed allylic substitution reactions.
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College , Chestnut Hill, Massachusetts 02467, United States.
authors.forename: Hwanjong
authors.initials: H
authors.lastname: Jang
authors.forename: Byunghyuck
authors.initials: B
authors.lastname: Jung
authors.forename: Amir H
authors.initials: AH
authors.lastname: Hoveyda
mesh_terms: D000466:Alkadienes / Q000737:chemistry*; D001896:Boron Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003300:Copper / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000466:Alkadienes; D001896:Boron Compounds; C025947:propadiene; D003300:Copper