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

• 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.

Ämnesord

NATURVETENSKAP  -- Kemi -- Organisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Organic Chemistry (hsv//eng)

Nyckelord

X-ray analyses

Conglomerate

CH/pi interactions

DNMR

Hindered

rotation barriers

DFT calculations

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