Enantioselective Synthesis of Substituted Piperidines by Addition of Aryl Grignard Reagents to Pyridine N-Oxides

Abstract

The synthesis of optically active piperidines by enantioselective addition of aryl Grignard reagents to pyridine N-oxides and lithium binolate followed by reduction is reported for the first time. The reaction results in high yields (51-94%) in combination with good ee (54-80%). Some of these products were subsequently recrystallized, affording enhanced optical purities (>99% ee).