[ILoveISO]

How would this work?

BrMgCH2CH2CH2CH2MgBr, THF

------------------------>
H, H2O

How does a grignard reaction work when there is two BrMg's present? The compound I start with is a 5 membered ring with a O at one of the points, carbonyl oxygen, and 2 methyl groups  at two different carbon corners.

Anyone got any idea? Thanks

[ILoveISO]

Also once the grignard opens up this lactone, how does the ring reform cause that is what the product ends up to be so I assume it had to have opened up then reformed...

[Dan]

Draw or explain properly. Preferably both.

[ILoveISO]

Okay basically it is a Lactone with 2 methyl groups at the top right and bottom left of the ring. (This is a 5 membered ring) Now it undergoes this reaction

BrMgCH2CH2CH2CH2MgBr, THF
----------------------------->
H+, H2O

My question is how does a grignard reagent work when there is TWO MgBr's in there? Where does it attack? The lactone will break apart but how will the ring reform?

[Dan]

Okay basically it is a Lactone with 2 methyl groups at the top right and bottom left of the ring. (This is a 5 membered ring)

This is exactly why we have nomenclature. Do you mean 3,5-dimethyldihydrofuran-2(3H)-one?

The lactone will break apart but how will the ring reform?

Have you been given the product's structure? What makes you think the "the ring" will reform?

Here's a question for you - if you treat ethyl acetate with two equivalents of MeMgBr, what do you get?