Carboxylate anions are more basic on the syn side because carboxylic acids are more stable with the proton syn to the carbonyl oxygen than anti. This led Gandour to propose that carboxylic anions should act as catalytic bases, as in enzymes, better on the syn side than the anti. However, numerous experimental tests have failed to reveal a strong preference. We resolve this problem by showing, on the basis of Linnett structures and MO calculations, that as a proton gradually departs from its firm syn position in the un-ionized COOH group, its preference for syn over anti diminishes rapidly, crossing over to a preference for anti before the midpoint of the reaction coordinate has been reached. Therefore in catalytic events, where the proton is partially transferred, the preference could favor either syn or anti and is small.