Stereoselective Synthesis of Spiropiperidines as BACE‑1 Aspartyl Protease Inhibitors via Late Stage <i>N</i>‑Arylation of a 1,8-Diazaspiro[4.5]dec-3-en-2-one Pharmacophore

A stereoselective synthesis of spiropiperidine compounds, exemplified by compound 1, was developed, which was based upon the late stage N-arylation of a 1,8-diazaspiro[4.5]­dec-3-en-2-one pharmacophore. Previously, compound 1 was prepared in low overall yield from piperidinone 2 via the Strecker reaction. A new route was developed, which employed the stereospecific Corey–Link reaction of an enantiomerically pure trichloromethylcarbinol to give a template compound amenable to late stage N-arylation.