Chandrasekhar, Sosale and Gorla, Suresh Kumar (2006) Novel cis–trans enantiomeric conglomerates: triage and absolute configurations via anomalous X-ray scattering. A photochemical second order asymmetric transformation. In: Tetrahedron: Asymmetry, 17 (15). pp. 2247-2251.
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Three tricyclic imides were prepared by a Diels–Alder reaction of 6-arylfulvenes and maleic anhydride, followed by treatment with $NH_3$. The exo isomers were found to exist as conglomerates when the aryl group was either p-tolyl or p-anisyl (although not phenyl). Triage of the p-tolyl racemate, followed by reaction with p-toluenesulfonyl chloride in $CH_2Cl_2/Et_3N$, led to the crystalline enantiopure Ntosylimides (these were also conglomerates). X-ray diﬀraction analysis of the N-tosylimides via the anomalous dispersion technique led to assignment of the absolute configurations (as either E or Z). The original p-tolyl imide enantiomers were found to racemize under UV irradiation in $CHCl_3$. Based on this, a possible second order asymmetric transformation under photochemical conditions was attempted, and indeed led to the isolation of crystalline imide with a small ee (\sim 15\%).
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Elsevier.|
|Department/Centre:||Division of Chemical Sciences > Organic Chemistry|
|Date Deposited:||30 Nov 2007|
|Last Modified:||19 Sep 2010 04:32|
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