was wondering if someone could help me write a mechanism for the synthesis of methyl E-4-methoxycinnamate from p-anisaldehyde. and suggest a reason why the cyclic intermediate might have two important groups in a trans relationship that could favor the E-alkene.
3 answers
Have you tried to draw a mechanism on one of these help boards. Tough to do. Actually, almost impossible to do.
How are you making it?
MeOAr-CHO + wittig -> MeOAr-CH=CHCOOMe
or a Wadsworth Emmons?
MeOAr-CHO + wittig -> MeOAr-CH=CHCOOMe
or a Wadsworth Emmons?
If it is a Wittig you should get the Z product unless it is the Schlosser Modification which gives the E product.
There is a good description of the Wittig mechanism on the Wikipedia page
http://en.wikipedia.org/wiki/Wittig_reaction
Which shows the cyclic transition state.
There is a good description of the Wittig mechanism on the Wikipedia page
http://en.wikipedia.org/wiki/Wittig_reaction
Which shows the cyclic transition state.