Synthesis of Highly Substituted N-Hydroxy Piperidine via Intramolecular Reductive Cyclization of 1-Keto-5-ketoxime

Diasteroselective synthesis of highly substituted N-hydroxypiperidine was achieved by an intramolecular reductive cyclization of monoxime (2) of the 1,5-diketone (1), generated from 2-(cyclohexylthio)-1-phenylethanone and arylaldehyde, using NaBH3CN. The major product N-hydroxypiperidine (3) has been found to be racemate of a single diastereomer.