[Synnr01]

Hi, I'm currently studying for a 3rd year organic resit exam (missed it first time due to bike accident) and in doing past-paper questions I have come up against some hurdles.
This is the major one, it should be a radical mechanism.

I tried the anionic C attacking the carbonyl C, then O attacking positive sulfur to form a 4-membered ring.
Then LDA abstracting a proton from the methyl and the C-O bond breaking

It doesn't look good, help would be greatly appreciated.

I've had another couple of problems centred on the appearance of extra C atoms. Here's an example.

The mechanism looks easy, but I can't work out where the 11th carbon in the product has come from.

Thanks for your help
Huw

[sjb]

Hi, I'm currently studying for a 3rd year organic resit exam (missed it first time due to bike accident) and in doing past-paper questions I have come up against some hurdles.
This is the major one, it should be a radical mechanism.

I tried the anionic C attacking the carbonyl C, then O attacking positive sulfur to form a 4-membered ring.
Then LDA abstracting a proton from the methyl and the C-O bond breaking

It doesn't look good, help would be greatly appreciated.

I've had another couple of problems centred on the appearance of extra C atoms. Here's an example.

The mechanism looks easy, but I can't work out where the 11th carbon in the product has come from.

Thanks for your help
Huw

See perhaps http://www.organic-chemistry.org/namedreactions/corey-chaykovsky-reaction.shtm? I think the first arrow relates to 3 separate reactions.