Question

Which electron pattern does not take place in an anti dihydroxylation reaction?

Answer 1

An anti-dihydroxylation reaction does not involve the removal of electrons from a double bond, but rather the addition of hydroxyl groups through nucleophilic attack.

Step-by-step explanation:

An anti-dihydroxylation reaction involves the addition of two hydroxyl groups to a carbon-carbon double bond. During this reaction, the electrons from the double bond are involved in the formation of new bonds. The electron pattern that does not take place in an anti-dihydroxylation reaction is the removal of electrons from the double bond, which would result in the formation of a carbocation. This is because the addition of hydroxyl groups requires a nucleophilic attack on the double bond, rather than the removal of electrons.

For example, in the reaction between an alkene and potassium permanganate, the alkene acts as a nucleophile and attacks the permanganate ion. The electrons from the double bond form new bonds with the hydroxyl groups, resulting in the addition of hydroxyl groups to the alkene.

Answer 2

The electron pattern not associated with anti dihydroxylation is the formation of cis-diol products, where hydroxyl groups are on the same side, opposed to the trans-diol products resulting from anti dihydroxylation.

Step-by-step explanation:

The electron pattern that does not take place in an anti dihydroxylation reaction is the formation of cis-diol products. Specifically, anti dihydroxylation involves the addition of hydroxyl groups (OH) across a double bond in such a way that the two OH groups are on opposite sides of the molecule, resulting in trans products. Therefore, the electron pattern involving the formation of cis products, where the hydroxyl groups end up on the same side of the molecule, is not consistent with anti dihydroxylation.

In the context given, we understand that the transformation of the precursor cis-allyl alcohol into a cyclic sulfate derivative fails to undergo a nucleophilic substitution to afford the desired isonucleoside. This inferred outcome suggests that the reaction went through an undesired pathway or did not achieve the expected anti addition of the reaction intermediates. Moreover, the note on the enzymatic specificity, as with fumarase reacting with fumarate but not with its enantiomer maleate, underscores that in organic chemistry, reactions are often stereospecific.