open access

https://hdl.handle.net/2115/97990

Phosphorus catalysis enabling α-sp3-C-H amination of 2-alkylpyridines

英語

2025-07-19

Royal Society of Chemistry

Organic chemistry frontiers

12(22)

6059-6069

Phosphorus-catalyzed sp3-C-H amination of 2-alkylpyridines was developed as a notable advancement of a catalytic sp3-C-H functionalization by an organophosphorus compound. Racemic 2,2 '-bis(diphenylphosphino)-1,1 '-binaphthyl (BINAP) acted as a particularly efficient catalyst precursor for the reaction of 2-alkylpyridines with dibutyl azodicarboxylate (DBAD) as an aminating agent in the presence of water and cesium carbonate as promoters in dichloromethane as a critical solvent, allowing the sp3-C-H amination under mild reaction conditions at 0 degrees C. The reaction proceeded exclusively at the C(alpha)-position even in the presence of more acidic C-H bonds. A quaternary azaphosphonium cation, generated by the reaction between BINAP and DBAD followed by solvolytic N-chloromethylation, is proposed to be the active catalyst that reacts directly with the alkylpyridine substrate.

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