Photochemically Enabled Total Syntheses of Stemoamide Alkaloids

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Natural Product Synthesis

Background:

• Photochemical transformations are versatile synthetic tools.
• Photoredox and photochemical reactivity are rapidly developing fields.
• Natural product synthesis often requires complex, multi-step approaches.

Purpose of the Study:

• To develop a modern photochemical synthetic strategy for natural product synthesis.
• To leverage radical reactivity for constructing complex molecular scaffolds.
• To synthesize three stemoamide alkaloids efficiently.

Main Methods:

• Iterative photochemical synthesis utilizing radical reactivity.
• Employing an acridinium photoredox catalyst for oxidative and reductive transformations.
• Utilizing polar radical crossover cycloaddition reactions.

Main Results:

• Construction of a densely functionalized tetrahydrofuran ring.
• Formation of a unique oxaspirocyclic butenolide via radical polar crossover.
• Access to three stemoamide alkaloids in the shortest sequences to date.

Conclusions:

• Photochemical synthetic strategies provide efficient and novel routes to complex natural products.
• This approach offers mild conditions and operationally simple procedures.
• Demonstrates a departure from traditional synthetic disconnections, highlighting a new synthetic methodology.