aajjeee

but why is it that in general wittig reactions lead to the cis product (the original attak is done in the most stable way, but the rotation to create the 4 member ring intermediate brings them closer) but this one sould lead to the trans product. (sidenote, i actually got pretty close to a racemic mix, with 56% trans-trans 44% cis trans. when i asked how i would differenciate them, i was asking nomenclature-wise (the 2nd and 3rd products are both trans-trans-diphénylbutadiène in my book, but they clearly are different)

im by no means an expert, but im pretty sure they will react diferently to magnetic fields, C13 will be visible in RMN but C12 wont. only isotopes that have a noticaeable difference in physical proprieties in my knowledge, are small ones (ie deuterium vs hydrogen) i am not an expert

I have done a Wittig reaction from cinnamaldehyde and Benzyl triphenyl phosphonium to obtain diphénylbutadiène (i might be using the french notation i have joined the reaction) and i am supposed to obtain a mix of trans-cis and trans-trans product, but while drawing them, i found 2 molecule each that would fit the description. my question is: is it true that only the top 2 (in the drawing) are found , and how can i distinguish the 1st & 4th and the 2nd & 3rd. I also added the mechanism which i drew, i find the 4th one to come more naturally, but the proffessor said his source found it to almost only give trans-trans product (edit) well i think there may be rotation just after the aldehyde is attacked, so only the most stable of the 2 possibilities of trans trans or cis-trans is formed and i would think that this is why you only observe 2 of the 4, But i am still wondering how you would differentiate them.