Question

Question: What alkene is needed to synthesize each 1,2-diol using [1] followed by NAHSO₃ in H₂O ; or [2] CH₃CO₃H followed by -OH in H₂O ?

a.

b.

c.

Short answer

Answer

a.

b.

c.

Step-by-step solution

Reaction of an alkene with osmium tetroxide

The reaction of an alkene with osmium tetroxide yields glycols.

The addition of hydroxyl group to an alkene follows syn addition (addition of substituents on the same face).

Reaction of an alkene with peracids

The reaction of an alkene with peracids, followed by a reaction with a base, yields a glycol.

The addition of a hydroxyl group to an alkene follows anti addition (addition of substituents on different faces).

The reaction proceeds through the formation of an epoxide.

Synthesis of a

Compound a can be synthesized as shown:

Synthesis of a

Synthesis of b

Compound b can be synthesized as shown:

Synthesis of b

Synthesis of c

Compound c can be synthesized as shown:

Synthesis of c