[fantastic_gorilla]

I desperately need help this lab question (http://imgur.com/gFiZB)! Going from the carbene to the bicyclic ketone is easy enough but I have no idea how to draw the mechanism from the bicyclic ketone (1) to the product sirenin.

Any suggestions would be much appreciated

[discodermolide]

Do you have any reagents? Perhaps from ref 3?

Looks like an aldol with formaldehyde, followed by ketone recuction to the alcohol followed by elimination.

[fantastic_gorilla]

Thanks for the help ! I'll try it.

ref 3 is a textbook chapter on carbenes. I've read it several times and haven't found anything helpful.

No reagents were given. Perhaps I'm only required to show the formation of the bicyclic ketone (1) but it seems too easy.

[discodermolide]

Reading the question you only have to show the mechanism for the formation of the bicyclic compound 1 from the carbene.