Concise Synthesis of 9,11-Secosteroids Pinnigorgiols B and E

Area of Science:

• Organic Chemistry
• Natural Product Synthesis
• Steroid Chemistry

Background:

• Pinnigorgiols B and E are 9,11-secosteroids.
• These compounds possess a unique tricyclic γ-diketone framework.

Purpose of the Study:

• To report the first synthesis of pinnigorgiols B and E.
• To develop an efficient synthetic route from readily available ergosterol.

Main Methods:

• Utilized a semipinacol rearrangement.
• Employed an acyl radical cyclization/hemiketalization cascade for skeleton assembly.

Main Results:

• Achieved the first synthesis of pinnigorgiols B and E.
• The cascade reaction efficiently formed the tricyclic γ-diketone core.
• Constructed two rings and three contiguous stereogenic centers in one step.

Conclusions:

• The developed synthetic strategy is effective for constructing complex secosteroids.
• This work provides access to valuable natural products from an inexpensive starting material.