The syntheses of several differently substituted amides formally derived from a chiral amine, either E-2-(2-hydroxyphenyl)cinnamic acid or both E- and Z-2-(2-hydroxynaphthyl)cinnamic acid, are reported. These molecules display a restricted rotation about the C2-Caryl bond. The barriers to rotation about the C2-Caryl bond were measured by the dynamic 1H NMR and were found to vary between 11.8 and 24.5 kcal mol-1, depending on the substitution. In particular, E-2-(2-hydroxynapthyl)cinnamic amides, displayed a high barrier to rotation (ΔGc‡ = 24.4 kcal mol-1) and could be isolated in both diastereomerically pure forms at room temperature. The X-ray structure of one E-2-(2-hydroxynapthyl)cinnamic amide, was resolved, enabling for the determination of the absolute configuration of the chiral axis (aR).

2-(2-Hydroxyaryl)cinnamic amides: a new class of axially chiral molecules

GALLI, SIMONA;MASCIOCCHI, NORBERTO;PIARULLI, UMBERTO
2006-01-01

Abstract

The syntheses of several differently substituted amides formally derived from a chiral amine, either E-2-(2-hydroxyphenyl)cinnamic acid or both E- and Z-2-(2-hydroxynaphthyl)cinnamic acid, are reported. These molecules display a restricted rotation about the C2-Caryl bond. The barriers to rotation about the C2-Caryl bond were measured by the dynamic 1H NMR and were found to vary between 11.8 and 24.5 kcal mol-1, depending on the substitution. In particular, E-2-(2-hydroxynapthyl)cinnamic amides, displayed a high barrier to rotation (ΔGc‡ = 24.4 kcal mol-1) and could be isolated in both diastereomerically pure forms at room temperature. The X-ray structure of one E-2-(2-hydroxynapthyl)cinnamic amide, was resolved, enabling for the determination of the absolute configuration of the chiral axis (aR).
2006
axial chirality; cinnamic acid; atropisomerism
Marelli, Chiara; Monti, Chiara; Galli, Simona; Masciocchi, Norberto; Piarulli, Umberto
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/1495099
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