Diastereoselective and Enantioselective Synthesis of Multi‐Functionalized Isoxazoline‐N‐Oxides through Asymmetric [4+1] Annulations

Abstract A diastereoselective and enantioselective formal [4+1] ylide annulation of chiral sulfonium salts with various substituted Morita‐Baylis‐Hillman (MBH) adducts leading to optically active isoxazoline N ‐oxides with three chiral carbon centers has been explored. The salient features of this methodology include a high diastereo‐ and enantioselective transformation, easily accessible starting materials, and mild reaction conditions. In addition, the isoxazoline N ‐oxides products can be conveniently transformed into functionalized compounds.