A novel building block for the synthesis of isofagomin analogues

The de novo synthesis of the novel potent building blocks phenyl (R)-3-acetoxymethyl-3,6-dihydro-2H-pyridine-1-carboxylate (−)-7 and phenyl (S)-3-butyryl-oxymethyl-3,6-dihydro-2H-pyridine-1-carboxylate (+)-8 starting from commercially available methyl-1-benzyl-4-oxo-3-piperidinecarboxylate is described. The key steps are the enantioselective esterification of the racemic alcohol 6 and the enantioselective hydrolysis of the racemic acetate 5, respectively, using lipase P from Pseudomonas caepacia.