First Synthesis of (±)-Retigeranic Acid

Key words

(±)-retigeranic acid - sesterterpene - Jones oxidation - Grignard reaction - Diels–Alder reaction - Wittig reaction - [2+2] cycloaddition - Corey–Seebach reaction - Criegee oxidation - aldol condensation - Pinnick oxidation

Significance

In 1985, Corey and co-workers reported the first racemic total synthesis of (±)-retigeranic acid. The pentacyclic sesterterpene has eight stereocenters. The key to their synthetic strategy was the construction of the central five-membered ring through a ring contraction sequence.

Comment

Carboxylic acid I was converted into the acyl chloride and after treatment with base, a [2+2] cycloaddition gave the ketone J. Cyclopentanone L was accessed by a ring expansion thereby assembling the carbon skeleton of (±)-retigeranic acid.

Publication History

Article published online:
16 August 2024