Late stage C-H functionalization via chalcogen and pnictogen salts

Area of Science:

• Organic Chemistry
• Medicinal Chemistry
• Synthetic Chemistry

Background:

• Late-stage functionalization (LSF) is crucial for accelerating structure-activity relationship (SAR) studies in drug discovery.
• Established LSF methods often rely on pre-functionalized heteroarenes (e.g., halides, boronic esters).
• Site-selective C-H functionalization offers a more direct and efficient approach to LSF.

Purpose of the Study:

• To review the synthesis and applications of three novel cationic groups as precursors for LSF.
• To highlight the utility of phosphonium, pyridinium, and thianthrenium salts in late-stage C-H functionalization.
• To emphasize the potential of these methods in medicinal chemistry.

Main Methods:

• Discussion of synthetic routes for generating phosphonium, pyridinium, and thianthrenium salts.
• Review of the application of these salts in site-selective C-H functionalization reactions.
• Analysis of the transformation of these cationic intermediates into diverse functional groups.

Main Results:

• Identification of three distinct cationic groups (phosphonium, pyridinium, thianthrenium) as versatile precursors for LSF.
• Demonstration that these salts can be introduced late stage to enable C-H functionalization.
• These methods provide access to a range of functionalized heteroarenes relevant to medicinal chemistry.

Conclusions:

• The reviewed cationic salts offer attractive alternatives for LSF, complementing existing methodologies.
• These approaches facilitate the rapid generation of molecular diversity for SAR studies.
• The discussed synthetic strategies hold significant promise for accelerating drug discovery programs.