title: In quest of factors that control the enantioselective catalytic Markovnikov hydroboration/oxidation of vinylarenes.
abstract: This study attempts to rationalise the unpredictable performance of transition metal catalysed asymmetric hydroboration of vinylarenes on varying the precursor of the catalyst from cationic to neutral species, [M(cod)(L-L)]BF4, [M(mu-Cl)(cod)]2/(L-L), the metal (M=Rh and Ir), and the hydroborating reagent (catecholborane, pinacolborane). The approaches are based on the agreement between experimental data provided by (R)-Binap and (R)-Quinap modified catalytic systems and computational data evidenced by DFT calculations and QM/MM strategies. Unprecedentedly high enantiomeric excesses in the hydroboration/oxidation of vinylarenes with both electron-withdrawing substituents ((R)-(+)-1-p-F-phenylethanol, ee up to 92 %) and electron-releasing substituents ((R)-(+)-1-p-MeO-phenylethanol, ee up to 98 %), can be attributed to a rhodium halide key intermediate.
authors.affiliation: Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Pl. Imperial Tàrraco 1, 43005 Tarragona, Spain.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Segarra
authors.forename: Elias
authors.initials: E
authors.lastname: Daura-Oller
authors.forename: Carmen
authors.initials: C
authors.lastname: Claver
authors.forename: Josep M
authors.initials: JM
authors.lastname: Poblet
authors.forename: Carles
authors.initials: C
authors.lastname: Bo
authors.forename: Elena
authors.initials: E
authors.lastname: Fernández