Preferential Crystallization of a Helicene-Viologen Hybrid - An Efficient Method to Resolve [5]Helquat Enantiomers on a 20 g Scale

0379101 - ÚOCHB 2013 RIV DE eng J - Journal Article
Vávra, Jan - Severa, Lukáš - Švec, Pavel - Císařová, I. - Koval, Dušan - Sázelová, Petra - Kašička, Václav - Teplý, Filip
Preferential Crystallization of a Helicene-Viologen Hybrid - An Efficient Method to Resolve [5]Helquat Enantiomers on a 20 g Scale.
European Journal of Organic Chemistry. -, č. 3 (2012), s. 489-499. ISSN 1434-193X. E-ISSN 1099-0690
R&D Projects: GA ČR GAP207/10/2391; GA ČR(CZ) GA203/08/1428; GA ČR GP203/09/P485
Institutional research plan: CEZ:AV0Z40550506
Keywords : helical structures * helicene-viologen hybrid * crystal growth * synthetic methods * conglomerates
Subject RIV: CC - Organic Chemistry
Impact factor: 3.344, year: 2012

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.
Permanent Link: http://hdl.handle.net/11104/0210371