Diels-Alder Reaction

[thE3nigma]

Hi,

This is not a homework question but something I found within my textbook. I just wanted to understand a solution they gave to the problem.

The question is:
Predict the product of the following Diels-Alder reaction:

The structures of two molecules, a diene (4 carbons long) and a methyl butyrate (methyl butanoate).

The answer has the methyl ester and H atom popping out of the book. I just wanted to confirm that it would not be wrong if it was drawn with the methyl ester and H atom going into the book would it? I do not think this is an endo substituent in this case.

[chemisttree]

Is methyl butyrate a dienophile? Not in my books.

[thE3nigma]

Sorry, I misspelled the molecules name. It is methyl 2-butenoate (I believe that is the correct name). There is a double bond between the second and third carbon after the COO- group.

[chemisttree]

... and is the diene cyclic? Is that methyl-2-butenoate E or Z?

[thE3nigma]

It is Z, the diene is not cyclic.

[chemisttree]

Endo isn't the right term to use in this system. Exo/endo is reserved for bicyclic compounds. (http://www.iupac.org/goldbook/E02094.pdf)

Both the methyl ester and the methyl group should be either up or down... syn fashion.