Hydrolysis of benzoates

The observed regioselectively in the introduction of the benzoate group was attributed to ring C in 144 assuming a lower energy twist-boat conformation thereby favouring nucleophilic attack at C(l). Base hydrolysis of benzoate 145 followed by demethylation of the resulting anisole derivative, furnished (+)-pancratistatin with an 11% overall yield from the meso diol. 

Hydrolysis of methyl ester Hydrolysis of benzoate ester N-dealkylation... 

As an example we can refer to nucleophilic catalysis of hydrolysis of benzoate esters by a phosphate buffer (Figure 5.4)... 

Eckert and coworkers have used a Hammett analysis to identify that the hydrolysis of benzoate esters in HTW occurs via acid and not base eatalysis (Scheme 3.3). The Hammett equation (eqn (3.12)) quantifies how substituents on a substrate bearing an X-substituted benzene ring alter tbe rate constant of a reaction k lk in comparison to the referenee aeid dissoei-ation of benzoic acid defined by ctx-... 

A-Heterocycles were synthesized via insertion of 1,1-dimethylallene into Pd-G bonds of cyclopalladated a-tetralone ketimines. Insertion reactions of alkynes into the Pd-G bond of cyclopalladated ferrocenylimines have also been described.Biomimetic hydrolysis of benzoates has been carried out with a water-soluble cyclopalladated aryl oxime, which was proposed as a potential green catalyst. Ghiral cyclopalladated liquid crystals 88 were obtained from amino acids and could possibly serve as enantioselective catalysts. " Palladacycle 89 has been derived from an anthracene-based Schiff base. 

Table 9.1 Rate constants at 250°C for the hydrolysis of benzoate esters, where is the equilibrium constant for the protonation of nonsubstituted ester ...

An example of a stepwise mechanism in which the sign of p is opposite for each individual step is flie acid-catalyzed hydrolysis of benzoates (pobs = +0.14) which shows a negative pi in the initial protonation step and a positive p2 during toe nucleophilic attack of water. 

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