Direct enantioselective approach to oxazolo[4,5-e]isoindoles from [(S)R]-1-aminosubstituted-4-(p-tolylsulfinyl)-1,3-butadienes

Abstract The enantioselective construction of [3a S ,5a R ,8a R ,8b R ]-1-( p -methoxyphenyl)-3a,7-dimethyl-3a,5a,8b,8a-tetrahydro-1 H -oxazolo[4,5- e ]isoindole-2,6,8-trione is achieved from enantiopure [(S) R ]-(1 E ,3 E )-2-methyl-1-( p -methoxyphenyl)amino-4-( p -tolylsulfinyl)-1,3-butadiene and N -methylmaleimide through a short sequence involving a Diels–Alder reaction, a sulfoxide–sulfenate rearrangement and intramolecular cyclization.