Asymmetric [4+1] Cycloadditions of N‐Thioacylimines and Sulfur Ylides

An asymmetric [4+1] cycloaddition reaction of N‐thioacylimines, generated in situ from α‐amido sulfones, and sulfur ylides bearing a d‐camphor scaffold, is reported. The enantiocontrol was significantly improved by adding catalytic amounts of (R)‐1,1′‐bi(2‐naphthol), furnishing a spectrum of 2‐alkylthio‐4,5‐dihydrothiazoles in modest to high yields with moderate to excellent stereoselectivity (>19:1 dr, up to 98% ee).