Site-Selective Pyridyl Alkyl Ketone Synthesis from N-Alkenoxypyridiniums through Boekelheide-Type Rearrangements.

The Boekelheide rearrangement is often employed for the oxy-functionalization of alkyl groups in the 2-position of pyridines, yet the corresponding alkylation reaction has so far not been realized since 1954. N-Alkenoxypyridinium functionalization has been widely applied to synthesize various carbonyl compounds by only using the carbonyl unit. Herein, we describe a simple yet efficient alkylation of N-alkenoxypyridiniums through the Boekelheide reaction for the synthesis of β-2-pyridyl alkyl ketones.