title: An efficient, practical, and enantioselective method for synthesis of homoallenylamides catalyzed by an aminoalcohol-derived, boron-based catalyst.
abstract: A practical catalytic method for enantioselective addition of an allene unit to aldimines is disclosed. Transformations are promoted by an in-situ-generated B-based catalyst that is derived from a simple, robust, and readily accessible (in multigram quantities) chiral aminoalcohol. A range of aryl-, heteroaryl-, and alkyl-substituted homoallenylamides can be obtained in 66-91% yield and 84:16 to >99:1 enantiomeric ratio through reactions performed at ambient temperature and in the presence of 0.1-3.0 mol% of the chiral catalyst and a commercially available allenylboron reagent. The catalytic protocol does not require strict anhydrous conditions, can be performed on gram scale, and promotes highly selective addition of an allenyl unit (vs a propargyl group). The utility of the approach is demonstrated through development of succinct approaches to syntheses of anisomycin and epi-cytoxazone.
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College , Chestnut Hill, Massachusetts 02467, United States.
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
authors.forename: Fredrik
authors.initials: F
authors.lastname: Haeffner
authors.forename: Amir H
authors.initials: AH
authors.lastname: Hoveyda
mesh_terms: D000466:Alkadienes / Q000138:chemical synthesis / Q000737:chemistry*; D000577:Amides / Q000138:chemical synthesis* / Q000737:chemistry; D000605:Amino Alcohols / Q000737:chemistry*; D001895:Boron / Q000737:chemistry*; D002384:Catalysis; D013237:Stereoisomerism
chemical_list: D000466:Alkadienes; D000577:Amides; D000605:Amino Alcohols; C025947:propadiene; D001895:Boron