Search for Conglomerate in Set of 7Helquat Salts: Multigram Resolution of Helicene-Viologen Hybrid by Preferential Crystallization.
Summary of "Search for Conglomerate in Set of 7Helquat Salts: Multigram Resolution of Helicene-Viologen Hybrid by Preferential Crystallization."
Investigation of a set of twelve helquat salts by X-ray crystal diffraction led to identification of conglomerate behavior in bis(trifluoroacetate) salt [CF3CO2]2. This is to demonstrate that systematic search for conglomerate can be performed for a given helicenoid enabling straightforward multigram resolution via preferential crystallization. Subsequently, preferential crystallization of this chiral helicene-viologen hybrid has been established to obtain pure P and M enantiomers in multigram scale, 5 grams each. Furthermore, preparation of non-racemic samples of helquat 2 via diastereomeric (R,R)-dibenzoyltartrate salts is described and determination of absolute configuration and racemization barrier is also reported.
This article was published in the following journal.
Name: The Journal of organic chemistry
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