SN2 Substitution Products: (2R, 3S)-3-methyl-2-methoxypentane

[assaftolko]

Homework Statement

Find the substitution products of ( 2S, 3S)-2-chloro-3-methylpentane + CH3O- in SN2 reaction.

The Attempt at a Solution

Will the anti-attack of the nucleophile result in the change of S to R for both the chiral carbons or just for the one with Cl connected to it? How can I know this?

 

[Saitama]

Homework Statement

Find the substitution products of ( 2S, 3S)-2-chloro-3-methylpentane + CH3O- in SN2 reaction.

The Attempt at a Solution

Will the anti-attack of the nucleophile result in the change of S to R for both the chiral carbons or just for the one with Cl connected to it? How can I know this?

The configuration of the carbon attached with Cl changes. The configuration changes only when the bonds to the chiral carbon break or change.

 

[assaftolko]

So I'll get (2R,3S)-3-methyl-2-pentanol?

 

[Saitama]

So I'll get (2R,3S)-3-methyl-2-pentanol?

How do you get an alcohol? Shouldn't that be an ether?

 

[assaftolko]

How can it be ether? Cl is the leaving group and you get OH that is attached to the Cl's carbon from the other side. Now This carbon is directly attached to O, H, R and R', I don't see how the oxygen can be attached to 2 carbons to form ether...

 

[chemisttree]

How can it be ether? Cl is the leaving group and you get OH that is attached to the Cl's carbon from the other side. Now This carbon is directly attached to O, H, R and R', I don't see how the oxygen can be attached to 2 carbons to form ether...

Williamson ether synthesis.

 

[Saitama]

Williamson ether synthesis.

Oh yes, that. I forgot the name of the reaction.

 

[HeavyMetal]

How can it be ether? Cl is the leaving group and you get OH that is attached to the Cl's carbon from the other side. Now This carbon is directly attached to O, H, R and R', I don't see how the oxygen can be attached to 2 carbons to form ether...

You said in your first post that the nucleophile was CH₃O^-, not OH^-. This would account for a carbon on one side of the oxygen. As this nucleophile attacks, it kicks away a Cl^-, causing inversion of configuration and a new bond to carbon. That makes the oxygen bridge two carbons, forming an ether. I believe the correct answer would be (2R, 3S)-3-methyl-2-methoxypentane.