Synthesis of N-hydroxy-r-2,c-6-diphenylpiperidines using DMD and their stereochemical studies by NMR spectra and semiempirical MO calculations

r-2,c-6-Diphenylpiperidin-4-ones 2-6 and r-2,c-6-diphenylpiperidine 7 are treated with DMD and the reaction is found to yield only the corresponding N-hydroxy derivatives 8-13. The preferred conformations of the N-hydroxy compounds 8-13 are analysed using the NMR spectra and semiempirical molecular orbital calculations. The N-hydroxy derivatives 8-13 are found to prefer distorted chair conformations.