I was studying the chemical properties of alkynes in which I found the following reaction with alcohols

Ethyne gas reacts with methanol to form methyl vinyl ether.
$$\ce{H-C≡C-H + CH3OH -> CH2=CH-OCH3}$$

Now I was quite surprised at seeing this reaction as in most of the other reactions(such as addition of acetic acid to ethyne). The electrophilic addition process was taking place twice. What I think is that $\ce{OCH3}$ must be a +M group (because of lone pairs on Oxygen atom, I suppose) and as a result the pi bond between the carbon atoms in methyl vinyl ether should break in the following way:

enter image description here

and then undergo another electrophilic addition reaction to form 1,1-dimethoxyethane (IUPAC nomenclature). Where am I wrong?

  • $\begingroup$ Under what conditions is this reaction reported to take place? $\endgroup$
    – Waylander
    Mar 23 at 9:32
  • $\begingroup$ I checked my notes and I found out that I havent written the condition for this reaction to proceed... neither did our teacher tell us the conditions under which this reaction has to be perfomed-as far as I can remember $\endgroup$
    – Adhway
    Mar 23 at 9:41
  • 2
    $\begingroup$ According to the literature this is done at high temperature and pressure in the presence of a basic metal catalyst and may be a radical process. It is certainly a high energy surface process and those are difficult to be precise about the mechanism. see pubs.rsc.org/en/content/articlelanding/2016/ra/c5ra25100a $\endgroup$
    – Waylander
    Mar 23 at 11:23


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