title: Chiral Brønsted acid catalyzed enantioselective synthesis of anti-homopropargyl alcohols via kinetic resolution-aldehyde allenylboration using racemic allenylboronates.
abstract: A chiral phosphoric acid catalyzed kinetic resolution/allenylboration of racemic allenylboronates with aldehydes is described. Allenylboration of aldehydes with 2.8 equiv of allenylboronate (±)-1 in the presence of 10 mol % of catalyst (R)-2 provided anti-homopropargyl alcohols 3 in 83-95% yield with 9:1 to 20:1 diastereoselectivity and 73-95% ee. The catalyst enables the kinetic resolution of the racemic allenylboronate (±)-1 to set the methyl stereocenter and biases the facial attack of the aldehyde to set the stereochemistry of the hydroxyl group in 3.
authors.affiliation: Department of Chemistry, Scripps Florida, Jupiter, Florida 33458, United States.
authors.forename: Andy S
authors.initials: AS
authors.lastname: Tsai
authors.forename: Ming
authors.initials: M
authors.lastname: Chen
authors.forename: William R
authors.initials: WR
authors.lastname: Roush
mesh_terms: D000438:Alcohols / Q000138:chemical synthesis* / Q000737:chemistry; D000447:Aldehydes / Q000737:chemistry*; D000466:Alkadienes / Q000737:chemistry*; D001896:Boron Compounds / Q000737:chemistry*; D002384:Catalysis; D007700:Kinetics; D015394:Molecular Structure; D010756:Phosphoric Acids / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000438:Alcohols; D000447:Aldehydes; D000466:Alkadienes; D001896:Boron Compounds; D010756:Phosphoric Acids