2-Pentenoic acid, 4-methyl-, ethyl ester → Ethyl (2E)-4-methyl-2-pentenoate

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Reaction Steps

On the other hand, the isomerization of ethyl 4-methyl-4-pentenoate to ethyl tratis-4-methyl-2-pentenoate is not favored thermodynamically. In fact the equilibrium distribution of isomers at 25° C. is as follows: ethyl 4-methyl-3-pentenoate (90%) and ethyl 4-methyl-2-pentenoate (10%). Despite this adverse equilibrium, ethyl 4- methyl-trans-2-pentenoate is obtained in 90% yield using the process of the present invention. The isomerization of ethyl 4-methyl-4-pentenoate also shows that this method accommodates the isomerization of olefin-esters that contain a tertiary carbon.

Provenance & Evidence