Concomitant morpholine ring contraction and pyridine lithiation in 4-morpholinopyridine: straightforward access to N-pyridyl oxazolidines

The reaction of 4-morpholinopyridine with TMSCH2Li induced an unprecedented anionic ring contraction of the morpholine ring in an exo-trig mode while lithiating the pyridine ring regioselectively at C-3. The one-pot process offers a straightforward route to functional oxazolidinyl pyridines.