[redfox]

Hi! I'm having a few problems with something and need to get to grips with it before my exam on Monday!
Electrocyclic reactions. Have attached pictures...

I need to know what the structure of the electrocyclisation products will be and what the name of
the type of electrocyclisation in D and E is.
I'm not just looking for answers tho, except for the last part. I assume for that the answer will give away
how I'm to determine what it is:)

Ta!

[azmanam]

start here:

http://stoltz.caltech.edu/litmtg/2003/zepernick-lit-4_21_03.pdf
http://web.uconn.edu/~ch351vc/cgi-bin/woodh1.pl

and here for everyone's favorite electrocyclization example, endiandric acid:
http://www.chemgapedia.de/vsengine/vlu/vsc/en/ch/12/oc/vlu_organik/biosynthesen/endiandrinsaeure/endiandrin.vlu/Page/vsc/en/ch/12/oc/biosynthesen/endiandrinsaeure/endiandric_chime.vscml.html

[redfox]

Ok, I've decided that in A, C1 and C4 will make a bond...is that correct?
I've only been taught that double bonds on the ends of molecules will shift...
is the same true for bonds in the middle of molecules?
Have said the same for B, which I know is wrong, just cos it looks the same
to me.
C I have no idea. Same again? *sigh*

[azmanam]

Well it really depends if it's photochemical or thermal.  You almost don't have enough information.  But if you assume your under the allowed conditions then you just need to know if is conrotatory or disrotatory.  Assume the ends of the double bonds will react.  The question is really after the stereochem of the products.

[redfox]

yeah, there really is very little info! It is conrotary tho.
Thanks for help:)