%0 Journal Article
%T The Preferred Ring-Tautomeric Form of a Bicyclic ¦Ã-Ketocarboxylic Acid: An Equilibrium Driven by Relief of Angular Hybridization Strain
%A Jesse K. Wong
%A Roger A. Lalancette and Hugh W. Thompsonb
%J The Open Crystallography Journal
%D 2008
%I 
%R 10.2174/1874846500801010056]
%X (¡À)-2-exo-Carboxy-2-endo-methyl-7-oxobicyclo[2.2.1]heptane exists preferentially in its closed, ringtautomer form, the tricyclic lactol (C9H12O3), which aggregates catemerically by forming hydroxyl-to-carbonyl hydrogen bonds [O......O = 2.7667(16) , O-H......O = 170o] among molecules screw related in b. This ring-chain equilibrium is driven by relief of angular strain at the 7-ketone, whose origin is the ketone¡¯s sp2 hybridization vs. the angle enforced by the bicyclic system. In the analogous compound with transposed functional groups, the equilibrium favors the keto acid, which is easily isolated.
%U http://www.benthamscience.com/open/tocryj/articles/V001/56TOCRYJ.htm