Final answer:
Dihydroxylation using OsO4 and H2O2, hydroboration, and the addition of H2 to alkenes are syn addition reactions, where the atoms or groups add to the same side of the alkene's double bond. option e is correct
Step-by-step explanation:
option e is correct The question pertains to the syn addition of substances to alkenes. Syn addition refers to the addition of substituents to the same side (or face) of the double bond in an alkene. Among the options given, dihydroxylation using OsO4 and H2O2 is a typical syn addition reaction, resulting in the addition of OH groups to the same side of the double bond. Another syn addition is the hydroboration process, where BH3 adds to the less substituted carbon first in a syn fashion, followed by oxidative workup to form an alcohol. The addition of H2 in the presence of a catalyst such as platinum also results in syn addition, producing an alkane.
Therefore, the correct options for syn addition are:
- Dihydroxylation using OsO4, H2O2
- Addition of H2
- Hydroboration
Option D, the addition of HCl, typically proceeds via an anti addition mechanism, adding the substituents on opposite sides of the double bond. Therefore, option D is not a syn addition reaction.
Syn addition occurs when two substituents are added to an alkene in a way that they end up on the same side (same face) of the double bond. Of the options given, the additions that occur in a syn fashion are hydroboration (option C) and dihydroxylation using OsO4, H2O2 (option A).