Quick Access to Optically Pure 2-(1-Hydroxybenzyl)piperidine and Pyrrolidine

Optically pure 2-(l-hydroxybenzyl)piperidine and pyrrolidine were prepared by reaction of oxygenated 2-(p-tolylsulfinyl)benzyl carbanions with the appropriate chlorinated N-sulfinylimines followed by subsequent elimination of the sulfinyl groups. The main reaction is a tandem process involving nucleophilic addition of the sulfinylbenzyl carbanion to the C=N bond followed by intramolecular elimination of the chlorine by the resulting amide. The matched pair of the reagents (exhibiting the same configuration at their respective sulfinyl moieties) evolves with a complete control of the stereoselectivity at the two newly created chiral carbons.