AN UNUSUAL REARRANGEMENT INVOLVING 5-BROMO-1-PHENYLPYRIDONE DURING ITS METHYL CROSS COUPLING WITH TURBO-GRIGNARD REAGENT, LEADING TO A 5-BROMOPYRIDONE-FUSED SEVEN-MEMBERED CARBOCYCLIC RING

Abstract

The structure of a cyclohepta[c]pyridin-1-one, a product of an unusual transformation, isolated during a turbo-Grignard reagentpromoted methyl cross coupling to 5-bromo-1-phenyl-2-pyridone, was determined by ¹H and ¹³C NMR, COSY, and high-resolution MS, as well as computer modeling. Its formation suggests a remarkable nucleophilic attack at the α-position to the pyridone carbonyl group. A rational pathway is presented.