What is the expected major organic product from the treatment of 4-methyl-2-pentyne with excess hydrogen in the presence of a platinum catalyst?

a. (E)-4-methyl-2-pentene
b. (Z)-4-methyl-2-pentene
c. (E)-2-methyl-2-pentene
d. (Z)-2-methyl-2-pentene
e. 2-methylpentene

Respuesta :

Answer:

(Z)-4-methyl-2-pentene

Explanation:

Hydrogenation  is a syn addition. This implies that the hydrogen atoms add to the same face of the multiple bond.

Hence, if we have the alkyne,  4-methyl-2-pentyne which reacts with excess hydrogen in the presence of a platinum catalyst, we obtain  (Z)-4-methyl-2-pentene since the hydrogen atoms add on the same side of the multiple bond.