Mechanism of reactions of unsaturated ethers and thioethers. VIII: Acid‐catalyzed addition of water to 1‐alkynyl ethers

Additional evidence for the occurrence of a rate determining proton transfer in the hydration of 1‐alkynyl ethers is afforded by the value of the solvent deuterium isotope effect, k /k = 1.7. The addition of water to 1‐ethoxy‐1‐propyne was investigated in a series of alcohol‐water mixtures. Application of the criterium of Grunwald indicates that a solvent molecule is not bound covalently in the slow proton transfer step.