Reaction mechanism for ketone and vinyl lithium

[brake4country]

Homework Statement

What is the product of 1-bromo-3-propanone treated with vinyl lithium?

Homework Equations

The Attempt at a Solution

I know that the carbonyl is attcked by the organolithium but I am having a hard time understanding how it attaches to the carbonyl since it is sp² hybridized. Any suggestions? Thanks!

 

[TeethWhitener]

Something must be wrong. 1-bromo-3-propanone is not a real molecule: propane only has 3 carbons, so a carbonyl on the 3-carbon would make it an aldehyde, not a ketone. Can you draw out the structure of the molecule that you intended to say?

 

[brake4country]

I believe my study manual meant 1-bromo-2-propanone. But, here is the reaction that I have determined so far, attached below. The answer only says that the vinyl lithium would add to the carbonyl. Thanks!

 

[TeethWhitener]

But, here is the reaction that I have determined so far, attached below.

I don't see the attachment.

I am having a hard time understanding how it attaches to the carbonyl since it is sp2 hybridized.

This shouldn't matter. Just treat the organolithium compound as approximately R^-Li⁺, with R = vinyl, and just do the same type of arrow-pushing you'd do with, e.g., butyllithium.

The one caveat is to think about not just the carbonyl, but the bromine as well.