[HongKongALevelboy]

can anyone tell me the mechanism for the conversion of triphenylmathanol to triphenylmethoxymethane , thx !

[movies]

The mechanism depends on what reagents you use.  The simplest method would be NaH + MeI.  The mechanism involves deprotonation of the alcohol, then S_N2 attack of the alkoxide on the methyl iodide.

[Mitch]

This doesn't scream carbocation intermediate to you?

[movies]

Depends how you do it, right?  If you used MeOH/HCl, then it would certainly be an S_N1 reaction mechanism, for sure.

[Mitch]

Perhaps, but I think this was how they trapped the first carbocations. I'll double check tomorrow, before I stick my foot any deeper.

[HongKongALevelboy]

sorry , i add something to my question , the catalyst is HCl , the reaction involves protonation of OH and it s a Sn1 reaction , that s all the question tells me . thx

[movies]

Okay, under those conditions it's definitely a carbocation intermediate.

I don't see how you could get to a carbocation if you used a base to deprotonate the alcohol though.

[Mitch]

I think when he says OH he means protonation of alcohol and not the addition of OH-

[movies]

Yeah, I think so too.

[Donaldson Tan]

let @ represent benzene ring

(1) @₃C-OH + H⁺ -> [ @₃C-OH₂ ]⁺

(2) [ @₃C-OH₂ ]⁺ -> [@₃C]⁺ + H₂O

(3) CH₃OH + [@₃C]⁺ -> @₃C-O-CH₃ + H⁺

The -OH group is protonated by aq HCl in reaction (1)
The protonated triphenylmethanol dissociates to form the carbocation and water in reaction (2).
A lone pair on the oxygen from methanol attacks the carbocation to form a C-O bond, thus cleaving the O-H bond in methanol to regenerate H⁺, in reaction (3).

This is a SN1 mechanism