title: Absolute Configuration Determination of Azulenyl Diols Isolated From Asymmetric Pinacol Coupling.
abstract: A convenient enantioselective approach for the pinacol coupling of 1-acetylazulene involving easily accessible (R)- or (S)-BINOLs as chiral additive is reported. This supposes the preformation of the chiral titanium-BINOL complex in 1:2 ratio and subsequent reduction with zinc when, 2,3-di(azulen-1-yl)butane-2,3-diol can be isolated in around 60% enantiomeric excess. The absolute configuration of the isolated enantiomers was assigned by comparison of the experimental and Boltzmann-weighted calculated VCD and ECD spectra and assigned as (+)-(2S;3S)-di(azulen-1-yl)butane-2,3-diol. Chirality 27:826-834, 2015. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Institute of Organic Chemistry "C. D. Nenitzescu" of the Romanian Academy, Splaiul Independentei, Bucharest, Romania.
authors.forename: Eugenia Andreea
authors.initials: EA
authors.lastname: Dragu
authors.affiliation: Spectropole-Optical and CD Spectroscopies, Service D1, Marseille, France.
authors.forename: Jean-Valere
authors.initials: JV
authors.lastname: Naubron
authors.affiliation: Institute of Organic Chemistry "C. D. Nenitzescu" of the Romanian Academy, Splaiul Independentei, Bucharest, Romania.
authors.forename: Anamaria
authors.initials: A
authors.lastname: Hanganu
authors.affiliation: Institute of Organic Chemistry "C. D. Nenitzescu" of the Romanian Academy, Splaiul Independentei, Bucharest, Romania.
authors.forename: Alexandru C
authors.initials: AC
authors.lastname: Razus
authors.affiliation: Institute of Organic Chemistry "C. D. Nenitzescu" of the Romanian Academy, Splaiul Independentei, Bucharest, Romania.
authors.forename: Simona
authors.initials: S
authors.lastname: Nica
keywords: 2,3-di(azulen-1-yl)butane-2,3-diol; asymmetric pinacol coupling; catalytic reactions; circular dichroism spectroscopy; theoretical calculations