Chiral bicyclo[3.3.1]-3,7-dioxanonane derivatives: Study of crystallization mode and conformational dynamics in solution

Summary, in English

A homologous series of chiral bis-ketals and mixed hemiketal-ketals with rigid bicyclo[3.3.1]-3,7-dioxanonane skeleton has been prepared. The crystallization mode (conglomerate or racemic compound) was established by chiral HPLC with double UV/polarimetric detection. The study of the solid-state structure by single crystal X-ray diffraction disclosed interesting CH ... pi intermolecular interactions. Hindering of rotation of phenyl groups at (hemi)ketalic centres was found to occur. A H-1-DNMR study gave activation barriers Delta G(#) of 15.9 kcal mol(-1) in the ketalic moiety and 10.3 kcal mol(-1) in the hemiketalic moiety. The experimental results were substantiated by MM and OFT calculations for ground and transition states. (c) 2011 Published by Elsevier B.V.

• Author: Cornelia Uncuta; Emeric Bartha; Dragos Gherase; Ioan Andrei Loas; Florina Teodorescu; Richard A. Varga; Nicolas Vanthuyne; Christian Roussel; Ulf Berg
• Department/s: Centre for Analysis and Synthesis
• Publishing year: 2011
• Language: English
• Pages: 20-30
• Publication/Series: Journal of Molecular Structure
• Volume: 989
• Issue: 1-3
• Links: http://dx.doi.org/10.1016/j.molstruc.2010.12.028
• Document type: Journal article
• Publisher: Elsevier
• Topic: Organic Chemistry
• Keywords: X-ray analyses; Conglomerate; CH/pi interactions; DNMR; Hindered; rotation barriers; DFT calculations
• Status: Published
• ISBN/ISSN/Other: ISSN: 0022-2860