[jjc]

I know that PCl5 reacts with alcohols by replacing the -OH group with Cl. Will that work if the -OH is attached to a double bonded carbon?

Meaning, C=C-OH, where the OH is attached to a carbon which is an alkene..

The answer key seems to suggest the reaction won't take place. But I'd like to know why.

Thanks!

[macman104]

The mechanism requires an SN2 attack, and therefore is not possible on a vinyl alcohol (that's what it's called when it's bonded to an alkene carbon)

Check out the powerpoint here, they have a very clear mechanism/description starting on slide 16.

[sjb]

Check out the powerpoint here, they have a very clear mechanism/description starting on slide 16.

Where?

In any event, are we assuming the vinyl alcohol exists as such, or as the carbonyl tautomer?

S

[macman104]

Whoops!

http://www.chem.wwu.edu/pavia/chap12a.ppt