[xshadow]

Where will Pyran be protonated?

Because I have:

- the Oxygen lone pair
-the double bond C=C


If will be protonated the oxygen I have a positve charge on oxygen  (but full  octect). No delocalization

If the C-sp2 will be protonated  I can get a Carbon sp2 with a positive charge that can be stabilized by resonance thanks the O lone pair(s). But, anyway ,C is a carbocation (not octect full)

So which is better?
Thanks

[pgk]

Let’s put the question in a different way:
Which protonated pyran form is more stable, the oxonium or the carbocation containing one?