Diastereoselective and Enantioselective Formal [4+1] Ylide Annulation Leading to Optically Active Isoxazoline N‐Oxides

A diastereoselective and enantioselective formal [4+1] ylide annulation of chiral sulfonium salts with various substituted α‐substituted nitroalkene leading to optically active isoxazoline N‐oxides using CF3SO3− as a key anion has been explored. The salient features of this methodology include high diastereo‐ and enantioselecties, easily available starting materials, mild reaction conditions, simple procedure, broad substrate scope and the isoxazoline N‐oxides are conveniently transformed into other functionalized compounds.