Cycloadditions [3+2] et [4+2] de lʹα-nitrosostyrène sur le 2-hydroxyméthylène indanone et ses dérivés

The preferred [3+2] cycloaddition before hetero-Diels–Alder reaction of 2-hydroxymethylene indanones derivatives with α-nitrosostyrene is described. New fused spiro-pyrroles-1′-oxide and spiro-1′,2′-oxazines structures are reported. The stereospecificity and regiospecificity of the cycloadditions are discussed.