Total Synthesis of (+)-Sinefungin

Area of Science:

• Organic Chemistry
• Medicinal Chemistry
• Antibiotic Synthesis

Background:

• Sinefungin is a nucleoside antibiotic with potential therapeutic applications.
• Previous synthesis routes may have limitations in stereochemical control or efficiency.
• The precise construction of stereocenters is crucial for biological activity.

Purpose of the Study:

• To develop an efficient asymmetric synthesis of sinefungin.
• To establish robust methods for constructing the C-6 and C-9 stereocenters.
• To overcome synthetic challenges in the final adenosylation step.

Main Methods:

• Asymmetric synthesis utilizing a diastereoselective allylation of an oxazolidinone derivative for C-6 stereochemistry.
• Curtius rearrangement to functionalize the C-6 position.
• Rhodium chiral bisphosphine-catalyzed asymmetric hydrogenation for C-9 amino acid stereochemistry.
• Vorbrüggen's protocol with persilylated N(6)-benzoyladenine for successful adenosylation.

Main Results:

• High diastereoselectivity (>99% de) achieved in the allylation step for C-6 amine stereochemistry.
• Efficient establishment of C-9 amino acid stereochemistry via asymmetric hydrogenation.
• Overcame difficulty in adenosylation by converting the C-6 urethane to an N-benzyl derivative.
• Successful sinefungin synthesis through optimized Vorbrüggen protocol.

Conclusions:

• A viable and efficient asymmetric synthesis of sinefungin has been developed.
• The synthetic strategy effectively controls key stereocenters (C-6 and C-9).
• The study provides a reliable method for constructing nucleoside analogs with potential pharmaceutical value.