79343-70-7Relevant articles and documents
HETERODIENE SYNTHESES-XXIV CHANGES IN THE REACTIVITY OF 2-OXOINDOLIN-3-YLIDENE DERIVATIVES WITH ETHYLVINYLETHER INDUCED BY ELECTRON-WITHDRAWING GROUPS. THE IMPORTANCE OF THE LUMO COEFFICIENTS
Righetti, P. P.,Gamba, A.,Tacconi, G.,Desimoni, G.
, p. 1779 - 1785 (2007/10/02)
Ethylvinylether reacts in acetonitrile with 1-acetyl-2-oxoindolin-3-ylidene derivatives β,β-disubstituted with electron-withdrawing substituents.When the β-substituents act by inductive effect alone, a regiospecific β-attack occured giving rise, through a 1,4-cycloaddition, to 2,3-dihydropyranindoles.As a by product Michael adduct can be obtained.When the β-substituent act by conjugative effect also, a regiospecific α-attack occured giving rise to spiro-dihydropyrane or-cyclobutane-2-oxoindolines depending on the nature of the substituents.In a less polar solvent, the latter ones are formed together with the adduct arising from the regioisomeric β attack.The overall reactivity can be rationalized in terms of LUMO coefficients of the heterodiene and of different stabilization offered by the solvent to the various reaction pathways.
