MOM-protected 3-hydroxy-5-phenyl-isoxazole: Regioselective preparation and synthetic application

Abstract Highly regioselective (>90%) MOM-protection of 3-hydroxy-5-phenyl-isoxazole, followed by elaboration in 4-position via directed ortho-metalation and mild deprotection with cold methanolic HCl provided ready access to a series of zwitterionic isoxazole derivatives.