title: Three-component asymmetric catalytic Ugi reaction--concinnity from diversity by substrate-mediated catalyst assembly.
abstract: The first chiral catalyst for the three-component Ugi reaction was identified as a result of a screen of a large set of different BOROX catalysts. The BOROX catalysts were assembled in situ from a chiral biaryl ligand, an amine, water, BH3·SMe2, and an alcohol or phenol. The catalyst screen included 13 different ligands, 12 amines, and 47 alcohols or phenols. The optimal catalyst system (LAP 8-5-47) provided α-amino amides from an aldehyde, a secondary amine, and an isonitrile with excellent asymmetric induction. The catalytically active species is proposed to be an ion pair that consists of the chiral boroxinate anion and an iminium cation.
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824 (USA) http://www2.chemistry.msu.edu/faculty/wulff/myweb26/index.htm.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zhao
authors.forename: Li
authors.initials: L
authors.lastname: Huang
authors.forename: Yong
authors.initials: Y
authors.lastname: Guan
authors.forename: William D
authors.initials: WD
authors.lastname: Wulff
mesh_terms: D000438:Alcohols; D000577:Amides / Q000737:chemistry*; D000588:Amines / Q000737:chemistry; D001896:Boron Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D008024:Ligands; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000438:Alcohols; D000577:Amides; D000588:Amines; D001896:Boron Compounds; D008024:Ligands; D009942:Organometallic Compounds
keywords: BOROX catalyst; Ugi reaction; asymmetric catalysis; multicomponent reactions; β-amino amides