Diastereoselective α‑Fluorination of N-tert-Butanesulfinyl Imidates

A diastereoselective α-fluorination of N-tert-butanesulfinyl imidates was developed. Deprotonation of N-tert-butanesulfinyl imidates with lithium hexamethyldisilazide generates aza-enolates that can be intercepted, with excellent diastereocontrol, by the inexpensive electrophilic fluorinating agent NFSI. This protocol was applied to the preparation of synthetically useful trans-2-fluoro-cyclohexamine with high enantiomeric purity (99.5% ee).