Vinyl ethers, hydrolysis

The mechanism of enamine hydrolysis is thus similar to that of vinyl ether hydrolysis (10-6). 

Studies of vinyl ether hydrolysis have demonstrated a strong retardation effect of jS-carboxy and /J-carbomethoxy groups (2000- to 25,000-fold). The rate profile for (Z)-/5-met boxy methacry lie acid indicates that ionization of the carboxylate raises the rate of hydrolysis by a factor of 240. It has been proposed that this difference in reactivity of ionized and non-ionized forms of the substrate is due to the conjugative and inductive effect of the substituents, rather than /5-lactone formation65,66. 

Ethyl vinyl ether hydrolysis 0-66 Kreevoy and Eliason, unpublished... 

Another approach to the problem of the value of n is to determine the degree of hydration of the transition state in an aprotic, nearly anhydrous, solvent. This has been done (Williams and Kreevoy, unpublished data) for ethyl vinyl ether hydrolysis in dimethylsulfoxide (DMSO). In nearly anhydrous DMSO containing very low concentrations of hydro-... 

Directly related to aldehyde-enol tautomerisation in protogenic solvents are recent results reported by Capon et al. (1979) concerning the decomposition of [61] in D20-[2H3]acetonitrile which generates vinyl alcohol (37), the tautomerisation of which was monitored by H and 13C nmr spectroscopy and compared with ethyl vinyl ether hydrolysis. 

Kresge, A. J., and Chiang, Y. Vinyl ether hydrolysis. V. Catalysis in dilute hydrofluoric acid solution. J. Amer. 

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