Metallation of pyridine N-oxides and application to synthesis

Abstract
Regio- and chemi-selective, directed ortho-lithiation of 2-, 2,5- or 3,4-substituted pyridine N-oxides has been achieved with diisopropylamide and butyllithium. Polysubstituted pyridine N-oxides, azaxanthone, and an isomer of orelline have been synthesized by such methods.