Synthesis of 2-Pyridinemethyl Ester Derivatives from Aldehydes and 2-Alkylheterocycle N-Oxides via Copper-Catalyzed Tandem Oxidative Coupling-Rearrangement

Successful benzylic C(sp³)-H acyloxylation of 2-alkylpyridine, 2-alkylpyrazine, and 2-alkylthiazole compounds was achieved using simple aldehydes. This was carried out via a copper-catalyzed tandem reaction, involving oxidative esterification followed by O-atom transfer of the resultant high yield formed Boekelheide intermediate. The method enables the preparation of functional heterocycles and the desymmetrization of 2,6-dialkylpyridines for efficient synthesis of dissymmetric pincer ligands, thus offering a new life for more practical Boekelheide rearrangement.