Direct Deaminative Halogenation at Hindered Tertiary Centers.

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Medicinal Chemistry

Background:

• Direct deaminative halogenation of alpha-tertiary amines, especially in complex 3D scaffolds, is challenging due to hindered C-N bond cleavage.
• Existing methods often struggle with sterically congested tertiary carbon centers.

Purpose of the Study:

• To develop a general and efficient method for direct deaminative halogenation of alpha-tertiary amines.
• To overcome limitations associated with C-N bond cleavage at congested tertiary carbon centers.
• To enable late-stage functionalization and diversification of amine-containing molecules.

Main Methods:

• Utilized a radical-mediated deaminative halogenation platform employing O-diphenylphosphinyl hydroxylamine.
• Modulated reaction conditions to favor halogen-atom transfer over hydrogenation.
• Developed a practical, one-pot transformation for halogenation.

Main Results:

• Achieved efficient chlorination, bromination, and iodination of sterically hindered tertiary amines.
• Demonstrated excellent functional group compatibility across a diverse range of substrates.
• Successfully synthesized valuable aryl-halide isosteres, including halogenated bicyclic and cage compounds.

Conclusions:

• The developed methodology provides a robust and scalable platform for the deaminative halogenation of challenging amine substrates.
• This approach facilitates late-stage molecular diversification, particularly for creating novel drug candidates.
• Opens new avenues for the synthesis of next-generation chlorine-containing pharmaceuticals.