Designing Fluorinated Cinchona Alkaloids for Enantioselective Catalysis: Controlling Internal Rotation by a Fluorine-Ammonium Ion gauche Effect (φNCCF) was written by Tanzer, Eva-Maria;Schweizer, W. Bernd;Ebert, Marc-Olivier;Gilmour, Ryan. And the article was included in Chemistry – A European Journal in 2012.Quality Control of (1S,2R,4S,5R)-1-Benzyl-2-(hydroxy(quinolin-4-yl)methyl)-5-vinylquinuclidin-1-ium chloride This article mentions the following:
The C9 position of cinchona alkaloids functions as a mol. hinge, with internal rotations around the C8-C9 (τ1) and C9-C4′ (τ2) bonds giving rise to four low energy conformers (1; anti-closed, anti-open, syn-closed, and syn-open). By substituting the C9 carbinol center by a configurationally defined fluorine substituent, a fluorine-ammonium ion gauche effect (σC-H→σC-F*; Fδ-···N+) encodes for two out of the four possible conformers (2). This constitutes a partial solution to the long-standing problem of governing internal rotations in cinchonium-based catalysts relying solely on a fluorine conformational effect. In the experiment, the researchers used many compounds, for example, (1S,2R,4S,5R)-1-Benzyl-2-(hydroxy(quinolin-4-yl)methyl)-5-vinylquinuclidin-1-ium chloride (cas: 69221-14-3Quality Control of (1S,2R,4S,5R)-1-Benzyl-2-(hydroxy(quinolin-4-yl)methyl)-5-vinylquinuclidin-1-ium chloride).
(1S,2R,4S,5R)-1-Benzyl-2-(hydroxy(quinolin-4-yl)methyl)-5-vinylquinuclidin-1-ium chloride (cas: 69221-14-3) belongs to quinuclidine derivatives. Quinuclidine exists in a number of naturally occurring compounds, biologically active agents, and privileged catalysts and ligands for asymmetric catalysis. The configuration at C-8 (quinuclidine attachment) and C-9 position (bearing hydroxy group) are important as they help in the orientation of hydroxy group and nitrogen atom of quinuclidine.Quality Control of (1S,2R,4S,5R)-1-Benzyl-2-(hydroxy(quinolin-4-yl)methyl)-5-vinylquinuclidin-1-ium chloride
Referemce:
Quinuclidine – Wikipedia,
Quinuclidine | C7H13N | ChemSpider