Question

The stereoselectivity of the wittig reaction is due in part to the choice of base and steric effects. True or False

Answer 1

The choice of base and steric effects do impact the stereoselectivity of the Wittig reaction.

Step-by-step explanation:

The statement is true. The stereoselectivity of the Wittig reaction is indeed influenced by the choice of base and steric effects. The Wittig reaction involves the formation of a carbon-carbon double bond, and the choice of base can determine the stereochemistry of the product.

For example, when using a sterically hindered base like lithium diisopropylamide (LDA), the reaction proceeds through an E2 elimination mechanism, leading to the formation of the more stable trans-alkene. On the other hand, when using a less hindered base like sodium hydroxide (NaOH), the reaction proceeds through an SN2 substitution mechanism, resulting in the formation of the less stable cis-alkene.

Therefore, the choice of base and steric effects play a significant role in determining the stereoselectivity of the Wittig reaction.

Answer 2

Answer:True

Explanation: The steroselectivity of the wittig reaction is due in part to the choice of base and steric effects , but largely controlled by electronic effects. Stabilized ylides appear to form the Eisomer of the alkene product, whereas unstabilized ylides tend to form the z isomer as the major product.