AbstractX‐ray crystal structure analysis was performed on single crystals of two diastereomeric enantiopure quinuclidines, (3R,8R)‐3‐vinyl‐8‐hydroxymethyl‐quinuclidine (quincoridine, QCD) and (3R,8S)‐3‐vinyl‐8‐hydroxymethyl‐quinuclidine (quincorine, QCI) as their salts with tartaric and p‐toluenesulphonate anions, respectively. The molecules of these quinuclidine derivatives are considered here as fragments of the Cinchona alkaloids, quinidine and quinine. A comparison of the conformational features of QCD, QCI, and Cinchona alkaloids in the crystalline state shows that the molecular geometry of the title compounds is similar to that of threo‐alkaloids (e.g., R,R isomer of epicinchonine) rather than to quinidine and quinine. The packing of the molecules in both structures is dominated by intermolecular hydrogen bonds. Chirality 16:180–189, 2004. © 2004 Wiley‐Liss, Inc.