Subject selenium electrophiles

Isoxazole-supported selenium resins, produced via 1,3-dipolar cycloaddition of nitrile oxides with propargyl selenium resin, were subjected to a-alkylation reactions with various electrophiles, leading to 3-aryl-5-i4-substituted ethenylisoxazoles in satisfactory yields (62-78%) and purity (90-99%). Compound 238 gave olefin 240, through selenoxide elimination from the a-alkylation product 239 (Scheme 56) <2003OL4649>. 

---