Dutch Resolution of a configurationally stable [5]helquat

• Published in: Chirality (New York, N.Y.) Vol. 30; no. 3; pp. 254 - 260
• Main Authors: Severa, Lukáš, Sázelová, Petra, Císařová, Ivana, Šaman, David, Koval, Dušan, Devadig, Pradeep, Kašička, Václav, Teplý, Filip
• Format: Journal Article
• Language: English
• Published: HOBOKEN Wiley 01.03.2018; Wiley Subscription Services, Inc
• Subjects: Ammonium; anion exchange; Anions; Cations; Chemistry; Chemistry, Analytical; Chemistry, Medicinal; Chemistry, Organic; chiral capillary electrophoresis; chirality assignment; Enantiomers; helical conformation; Life Sciences & Biomedicine; Pharmacology & Pharmacy; Physical Sciences; Racemization; racemization barrier; Science & Technology; single enantiomers; tartrate anions family; HELQUATS; tartrate anions family; DYES; racemization barrier; CHIROPTICAL PROPERTIES; OPTICAL-PROPERTIES; helical conformation; ONE HUNDRED YEARS; HELICENES; single enantiomers; chirality assignment; FAMILIES; ENHANCEMENT; chiral capillary electrophoresis; anion exchange; CHIRALITY; DERIVATIVES
• ISSN: 0899-0042; 1520-636X
• DOI: 10.1002/chir.22789

Synthesis and nontrivial optical resolution of a helicene‐like dication, helquat 1, has been accomplished. Starting with gram scale of the racemic helquat 1 sample, Dutch Resolution using family of 3 tartrate anions was key to achieve successful separation of M and P helical enantiomers of 1. Hundreds of milligrams of each enantiomer of this configurationally stable C2‐symmetric helquat have been obtained. Racemization barrier of 1 has been determined. To our knowledge this is the first report on Dutch Resolution performed with a helicene‐like compound. Moreover, there are no literature precedents for Dutch Resolution of chiral quaternary ammonium cations. Racemic helquat 1 has been resolved by using Dutch Resolution. Using family of three tartrate anion derivatives, hundreds of milligrams of each enantiomeric salt, [P‐1][Br]2 and [M‐1][Br]2, have been obtained in high optical purity (98% ee). This is the first report on Dutch Resolution performed with a helicene‐like compound as well as the first such resolution with chiral quaternary ammonium cation.