Nineteen-step total synthesis of (+)-phorbol

Area of Science:

• Organic Chemistry
• Natural Product Synthesis
• Medicinal Chemistry

Background:

• Phorbol, a tigliane diterpene, is known for its complex structure and potential medicinal applications.
• Current methods for obtaining phorbol and its analogues, isolation and semisynthesis, are limited.
• Total chemical synthesis of enantiopure phorbol has been hindered by its structural complexity.

Purpose of the Study:

• To develop a novel, efficient strategy for the enantiospecific total synthesis of (+)-phorbol.
• To enable access to previously inaccessible phorbol analogues with unique oxygenation patterns.
• To explore the utility of a two-phase terpene biosynthesis strategy in complex molecule synthesis.

Main Methods:

• Implementation of a two-phase terpene synthesis strategy, inspired by natural biosynthesis.
• Utilized powerful carbon-carbon bond constructions and carbon-hydrogen bond oxidations.
• Employed (+)-3-carene, an abundant monoterpene, as the starting material.

Main Results:

• Achieved the enantiospecific total synthesis of (+)-phorbol in a record 19 steps.
• Demonstrated the feasibility of the two-phase synthesis strategy for complex diterpenes.
• The synthetic route provides a platform for generating novel phorbol analogues.

Conclusions:

• The developed synthetic route offers a viable alternative to traditional methods for accessing phorbol derivatives.
• This synthesis opens avenues for exploring the medicinal potential of novel phorbol analogues.
• The strategy highlights the power of biomimetic approaches in complex organic synthesis.