Regio- and stereoselective C-H functionalization of brassinosteroids

Area of Science:

• Organic Chemistry
• Natural Product Synthesis
• Catalysis

Background:

• Late-stage functionalization is crucial for modifying complex natural products.
• Brassinosteroids are plant hormones with significant biological activity.
• Developing selective synthetic methods for brassinosteroids is an ongoing challenge.

Purpose of the Study:

• To report a novel rhodium-catalyzed reaction for the late-stage functionalization of brassinosteroids.
• To achieve regio- and stereoselective modification at the C15 position.
• To demonstrate the utility of the functionalized brassinosteroids for further derivatization.

Main Methods:

• Rhodium-catalyzed C-H functionalization reaction.
• Reaction of brassinosteroids with aryloxysulfonamides.
• Stereoselective synthesis and purification of the C15-functionalized product.
• Conjugation of the brassinosteroid derivative with a BODIPY dye.

Main Results:

• The rhodium-catalyzed reaction selectively functionalized brassinosteroids at the C15 position with high regio- and stereoselectivity.
• 24-epibrassinolide was successfully modified at C15.
• The resulting brassinosteroid derivative was readily conjugated with a BODIPY dye.
• The BODIPY conjugate retained the native functional groups of the brassinosteroid.

Conclusions:

• A new method for selective C15 functionalization of brassinosteroids has been developed using rhodium catalysis.
• This method provides access to novel brassinosteroid derivatives with potential applications in chemical biology and drug discovery.
• The preservation of native functional groups facilitates the creation of complex molecular architectures.