Efficient Route to (2R)-6-Hydroxy-2-methyl- dihydropyridin-3-ones, Key Intermediates for Piperidine Alkaloids Syntheses

The efficient synthesis of (2R,6S)-6-hydroxy-2-methyl-1-tosyl-1,2-dihydropyridin-3(6H)-one 5 in five steps and 30 % overall yield is reported. This dihydropyridone constitutes versatile chiral building block repetitively used in the synthesis of various piperidine alkaloids and may serve as key template for the construction of synthetic libraries of bioactive derivatives and analogues of the piperidine alkaloids.