Regioselective reduction of N-alkyl-3-sulfonyl glutarimides. Synthesis of 3,4-dihydro-3-tosylpyridin-2-ones

Treatment of N-alkyl-3-sulfonyl glutarimides (1) with sodium hydride and then lithium aluminum hydride could give regioselective reduced hydroxy piperidones (5) which were further dehydrated to 3,4-dihydro-3-tosylpyridin-2-ones (6) in the presence of boron trifluoride.