Diastereoselective Synthesis of Nitropiperidones from N-p-Tolylsulfinyl β-Nitroamines

Significance

Described is a simple three-step strategy for the diastereoselective synthesis of substituted 5-nitropiperidones, employing Michael addition of 1 to α,β-unsaturated esters, followed by a strong cation exchange (SCX) column, reductive desulfonylation and cyclization of the resulting free amine to yield the nitropiperidone products. The reactions proceed with modest to high diastereoselectivity. Mild conditions and only one chromatographic purification are the main features of the process. The synthesis of optically active N-p-tolylsulfinyl β-nitroamines 1 involves treatment of nitromethane with a wide variety of N-p-tolylsulfonylimines.