[chrisr789]

I am trying to name a product using the trivial name of the starting material and as suffix. The starting material contains a diene, and the reaction involves a Diels-Alder cycloaddition. In the name of the product I need to somehow unambiguously state that the previous diene has now become a lonely double bond, i.e. C=C-C=C has become C-C=C-C. If we call the four carbons 1, 2, 3 and 4, I can use 1,4-dihydro...but do you think this is sufficient? All thought most welcome...

edit: actually, as 1 and 4 have now formed new bonds to other carbons, can I even write 1,4-dihydro?!

[rucik5]

Hey,
could you not use the IUPAC name? Well, in theory you had a diene and now you just have an alkene - so I don't think that you should refer to an alkene as 1,4-dihydro diene. I can't see the entire structure, but you never call C-C=C-C a 1,4 dihydro-something, you'd call it something-2-ene.

[chrisr789]

I can't use a fully systematic name no, it's a large natural product. I wouldn't be referring to the product alkene as a 1,4-dihydro diene because it's not a diene. But as the base name contains a diene and the product contains a single olefin group, the name would have refer to the saturation at the terminal carbons but not at C2 and C3, so I'm thinking something a long the lines of "1,4-dihydro-2-ene-". See any problems with that?

[fledarmus]

For a discussion of reactions of a natural product, I wouldn't have any problems with using 'dihydro' to indicate the change from diene to alkene, but I would stick to the IUPAC numbering system rather than calling it arbitrarily a 1,4-dihydro diene. For example, if the natural product was chrisr789ane and the diene was between the 13,14 and 15,16 carbons, calling the alkene "13,16-dihydrochrisr789ane" seems to me to be good enough. Then you could just add the substituents, eg "13-methoxy-16-sulfonamido-13,16-dihydrochrisr789ane"

[chrisr789]

For a discussion of reactions of a natural product, I wouldn't have any problems with using 'dihydro' to indicate the change from diene to alkene, but I would stick to the IUPAC numbering system rather than calling it arbitrarily a 1,4-dihydro diene. For example, if the natural product was chrisr789ane and the diene was between the 13,14 and 15,16 carbons, calling the alkene "13,16-dihydrochrisr789ane" seems to me to be good enough. Then you could just add the substituents, eg "13-methoxy-16-sulfonamido-13,16-dihydrochrisr789ane"

Yeah I was just using the numbers for the purposes of discussing it here...there's a standard numbering system of the class of compounds I'm using so I'll be sticking to that. Thanks both of you for your input.

[jlbradfi]

C=C-C=C 1,3-butadiene
C-C=C-C  2-butene