title: A hydrogen bond rationale for the enantioselective β-alkenylboration of enones catalyzed by O-monoacyltartaric acids.
abstract: DFT calculations suggest that O-monoacyl L-tartaric acids catalyze the asymmetric conjugate alkenylboration of enones through transition structures that are stabilized by hydrogen-bonding interactions. Formation of a five-membered acyloxyborane is proposed. The hydrogen of the free carboxy group derived from the catalyst interacts with the carbonyl group of the cyclic acyloxyborane, stabilizing the transition structure and reducing the flexibility of the system. Additional stabilizing nonclassical CH···O hydrogen-bond interactions seem to determine the observed enantioselectivity.
authors.affiliation: Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario , Suipacha 531, Rosario 2000, Argentina.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Grimblat
authors.forename: Masaharu
authors.initials: M
authors.lastname: Sugiura
authors.forename: Silvina C
authors.initials: SC
authors.lastname: Pellegrinet
mesh_terms: D001880:Boranes / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D006860:Hydrogen Bonding; D007659:Ketones / Q000737:chemistry*; D008968:Molecular Conformation; D013237:Stereoisomerism; D013644:Tartrates / Q000737:chemistry*
chemical_list: D001880:Boranes; D007659:Ketones; D013644:Tartrates; C029768:tartaric acid