Woodward Reaction

What is Woodward Reaction?

Woodward Hydroxylation is the synthesis of syn-diols or cis-diols from alkenes. This reaction is named after an American organic chemist, Robert Burns Woodward. When alkene is treated with iodine and silver acetate, it will undergo nucleophilic displacement with acetate in the presence of water. The intermediate product gives the desired diols on hydrolysis.

Woodward reaction of an anion with a double bond may be regarded as close to an SN2 displacement – one of the two bonds of that double bond being displaced, by backside attack with the stereochemistry that is hard in certain cases.

Woodward Hydroxylation

Woodward Hydroxylation

The reaction is cis-hydroxylation of an alkene and is known as Woodward cis-hydroxylation, after the name of its discoverer R.B. Woodward.

Woodward Reaction Mechanism

The woodward reaction allows the synthesis of syn-diols from alkenes by the addition of iodine followed by nucleophilic displacement with acetate in the presence of water. Hydrolysis of the intermediate ester gives the desired diol.

The steps involved in the mechanism of woodward reaction are listed below.

  1. Iodine reacts with alkene forming a cyclic iodonium intermediate.
  2. Further, the cyclic intermediate reacts with acetate ion in SN2 fashion to form a five-membered ring compound.
  3. The five-membered rings are opened by Hydrolysis reaction.
  4. Further protonation followed by hydrolysis gives the corresponding diols.
Woodward Reaction Mechanism

Woodward Reaction Mechanism