[everydaygame]

Hi there, Im trying to figure this out. I know the reaction and i can see for both of them how the enolate will form and give alkylation but then there is a cyclisation which im not sure of the mechanism for. Anyone have any suggestions on how it might go or what name I might be able to find it under in a text book?

http://i248.photobucket.com/albums/gg181/rulerpen/rofl.jpg

[Dan]

Look up acetal formation and the isopropylidene (aka acetonide) protecting group. Isopropylidene is a very common protecting group for (mainly 1,2-)diols.

[Rico]

Hey everydaygame

The cyclization in your reactions is a simple acetaleformation from a diol. You can find the mechanism in almost every organic chemistry textbooks, but to help you i have drawn the mechanism of the acetaleformation in the first reaction (see jpeg attached). The diol is produced in both reactions from reductions with lithiumaluminumhydride. I havent drawn the mechanism for the acetalformation in reaction number 2, but it goes in the same way as the one i have drawn and then you can try that one out for yourself.

Rico

[AWK]

The cyclization in your reactions is a simple acetaleformation from a diol.

Rather ketal formation!

[Rico]

The cyclization in your reactions is a simple acetaleformation from a diol.

Rather ketal formation!

If you insist 

[everydaygame]

Thanks all of you thats great and out of interest Rico what are you using to draw your mechanisms? 

[Rico]

To these drawings I have used MDL ISIS Draw. It can be downloaded for free for non-commercial use at www.mdl.com. You just need to register and create an account.

Rico