[spirochete]

I have searched many pages of google with no success.  Does anybody have a link to a movie of the diels alder reaction, including formation of the transition state?

[agrobert]

http://video.google.com/videoplay?docid=-4399348260216120982&q=diels+alder&total=7&start=0&num=10&so=0&type=search&plindex=1

and others linked from Google Video

[redskytonight820]

Diels-Alder isn't too hard once you get the hang of it!

Just break the double bond, draw the dotted lines from both carbons that the dbl bond was previously on, and connect to other carbons on the other molecule, and you're set.

[agrobert]

Diels-Alder isn't too hard once you get the hang of it!

Just break the double bond, draw the dotted lines from both carbons that the dbl bond was previously on, and connect to other carbons on the other molecule, and you're set.

?

[macman104]

Diels-Alder isn't too hard once you get the hang of it!

Just break the double bond, draw the dotted lines from both carbons that the dbl bond was previously on, and connect to other carbons on the other molecule, and you're set.

Ah, yes, but when you deal with HOMO-LUMO issues and which substituents are going to end up facing up/down, that is always the confusing part.  If I'm dealing with a ring and endo/exo, then it's usually not a problem.  However, acyclic DA reactions are a tossup for me (I usually just flip a coin for the position of the substiuents).

[sjb]

However, acyclic DA reactions are a tossup for me (I usually just flip a coin for the position of the substiuents).

If there's only one substituent on diene and dieneophile, as in e.g. nitroethylene and penta-1,3-diene, or nitroethylene and 2-methylbuta-1,3-diene; a rough and ready answer can be surmised by suggesting that the Diels Alder is "ortho-para directing" - it does have some basis in orbital theory but is perhaps a bit complicated to describe on a forum like this.

I think there's a reasonably easy explanation in http://www.amazon.co.uk/Pericyclic-Reactions-Oxford-Chemistry-Primers/dp/0198503075

Is that the problem you mean?

S

[macman104]

Indeed sjb, the orbital picture on the cover of that book is what I'm talking about.  It's no worry though, I've never been very good with orbital theory and the like.  MO, HOMO, LUMO, etc have never been a strong suit in my organic knowledge.

[spirochete]

Thanks for the link I completely forgot about google video/you tube.

Diels-Alder isn't too hard once you get the hang of it!

Just break the double bond, draw the dotted lines from both carbons that the dbl bond was previously on, and connect to other carbons on the other molecule, and you're set.

The strange thing is I have no problem predicting products and whatnot, it's just that when it comes to stereochemistry I can't always visualize exactly how the product came to be.  I hate feeling like I'm drawing dashes and wedges based on an arbitrary rule, and I've been able to avoid that up until this rxn. 

I should get it eventually by playing around with models. 

[davej]

Don't know if this is exactly what you are talking about, as I don't exactly remember Diels Alder reaction, but maybe look at this? http://www.asu.edu/courses/chm331/notes/conjugated/visualize/fingersthumbs.mov