Rapid and Stereoselective Access to 6″-Amino-6″-deoxy-α-GalCer Scaffolds

Area of Science:

• Carbohydrate Chemistry
• Immunology
• Organic Synthesis

Background:

• α-Galactosylceramides (α-GalCer) are crucial glycolipids that modulate immune responses via NKT cells.
• Synthesizing diverse α-GalCer analogues for structure-activity relationship studies is challenging.
• Existing synthetic routes often lack efficiency and scalability for producing modified analogues.

Purpose of the Study:

• To develop a highly efficient and scalable synthetic route for orthogonally protected α-galactosylphytosphingosine (α-GalPhyt).
• To enable rapid synthesis of various 6″-N-modified α-GalCer analogues from a common intermediate.
• To demonstrate the utility of the developed method by synthesizing known and novel α-GalCer agonists.

Main Methods:

• Utilized a d-galactal-derived 1,2-anhydro donor for α-selective glycosylation with a sphingoid acceptor.
• Employed orthogonal deprotection strategies for selective modification at the galactose C-6″ or sphingoid C-2 positions.
• Synthesized NU-α-GalCer and a novel 7DW8-5 analogue using the key α-GalPhyt intermediate.

Main Results:

• Established a highly efficient route to orthogonally protected α-GalPhyt.
• Demonstrated rapid and on-scale synthesis of 6″-N-modified α-GalCer analogues.
• Successfully synthesized the potent NK T cell agonist NU-α-GalCer and a novel 7DW8-5 analogue.

Conclusions:

• The developed synthetic strategy provides a versatile platform for accessing diverse α-GalCer analogues.
• This method facilitates the efficient production of immunomodulatory glycolipids for immunological research.
• The approach allows for rapid exploration of structure-activity relationships in α-GalCer-based therapeutics.