CuOTf‐Catalyzed Selective Generation of 2‐Aminopyrimidines from Carbodiimides and Diaryliodonium Salts by a Triple C(sp3)−H Functionalization

The selective C(sp3)−H bond functionalization is an ideal and atom‐economical method in organic synthesis. In this work, 2‐aminopyrimidines are generated from a Cu‐catalyzed reaction between carbodiimides and diaryliodonium salts, by cleavage of four C(sp3)−H, one C−N, and one C=N bonds in the carbodiimides. It is the first triple C(sp3)−H bond functionalization neighboring a C=N bond. The selective synthesis of 2‐aminopyrimidines is controlled by the amount of the diaryliodonium salts. The novel mechanism involving a C−N formation/1,5‐H shift/1,7‐H shift/6 π‐electrocyclic ring‐closing/aromatization is well elucidated by the detection of important intermediates and DFT calculations. Triple C(sp3)‐H Functionalization: Two Cu‐catalyzed reactions between carbodiimides and diaryliodonium salts are achieved to provide various amino‐substituted pyrimidines. The selective synthesis of 2‐aminopyrimidines is controlled by the amount of diaryliodonium salts. It is the first triple C(sp3)−H functionalization neighboring a C=N bond. The novel mechanism via C‐N formation/1,5‐H shift/1,7‐H shift/6π‐ERC/aromatization (ERC=electrocyclic ring‐closing) for 2‐aminopyrimidines is well elucidated by the detection of intermediates and DFT calculation.