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Preferential Crystallization of a Helicene–Viologen Hybrid – An Efficient Method to Resolve [5]Helquat Enantiomers on a 20 g Scale
Author(s) -
Vávra Jan,
Severa Lukáš,
Švec Pavel,
Císařová Ivana,
Koval Dušan,
Sázelová Petra,
Kašička Václav,
Teplý Filip
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201101367
Subject(s) - helicene , enantiomer , chemistry , crystallization , viologen , chiral resolution , resolution (logic) , stereochemistry , organic chemistry , combinatorial chemistry , molecule , artificial intelligence , computer science
The bistriflate salt of racemic [5]helquat 1 was found to form a conglomerate. Based on this finding, the preferential crystallization of this chiral helicene–viologen hybrid was developed to deliver pure enantiomers on a 20 g scale (10.5 g of each enantiomer). To the best of our knowledge, this is the largest amount of nonracemic helicene‐like compound obtained by preferential crystallization to date. The absolute configuration of the P enantiomer was confirmed by X‐ray crystal structure analysis. The chromatography‐free synthesis of racemic 1 on a multigram scale (30 g) is also presented as an entry point to this resolution study.