Collect. Czech. Chem. Commun. 2000, 65, 673-694

Sterically Crowded Hexaalkyl Benzene-1,2,3,4,5,6-hexakis[α-(alkoxycarbonyl)propanoates]. Synthesis and Conformation Analysis

Daniel Alexandera, Stanislav Böhmb, Ivana Císařovác, Petr Holýa, Jaroslav Podlahac, Miroslav Šloufc and Jiří Závadaa,*

a Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague, Czech Republic
b Department of Organic Chemistry, Prague Institute of Chemical Technology, 166 28 Prague, Czech Republic
c Department of Inorganic Chemistry, Faculty of Science, Charles University, 128 40 Prague, Czech Republic


A selective hexa-fold monoalkylation of the malonester carbanion (-)CH(COOR)2 (R = Me, Et, t-Bu, Bn) with hexakis(bromomethyl)benzene afforded the title compounds 3 in a high-yield reactions. On subsequent replacement of the acid α-hydrogens with bulkier substituents, the title compounds 3, R = Et, provided a broad variety of the α-X-persubstituted homologues and derivatives 4 (X = Me, Et, Bu, Oc, Bn, Br, N3). The effect of the variable X substituent on conformation was investigated by single-crystal X-ray diffraction and compared with the results obtained by theoretical calculation.

Keywords: Alkylations; Carbanions; Multiarmed compounds; Benzenes; Malonates; Molecular mechanics; Semiempirical calculations; X-Ray diffraction; Conformation analysis.

References: 26 live references.