Producción Científica Profesorado

Chemoselective intramolecular annulation of 3-alkylindolines into dihydro or tetrahydrofuro[2,3-b]indoles



Suárez Castillo, Oscar Rodolfo

1997

Chemoselective intramolecular annulation of 3-alkylindolines into dihydro or tetrahydrofuro[2,3-b]indoles. Suárez-Castillo O. R., García-Velgara M., Morales-Ríos M. S., Joseph-Nathan P. DOI: 10.1139/v97-115


Abstract


3-Alkyl-2-hydroxyindolines, conveniently prepared from 2-hydroxyindolenines and a Grignard reagent, cyclize in the aprotic solvent tetrahydrofuran to afford tetrahydro-3-cyano-2-oxofuro[2,3-b]indoles, while in the protic solvent methanol the chemoselectivity changed to give dihydro-2-amino-3-carbomethoxyfuro[2,3-b]indoles. The steric effect of the alkyl group on the reactivity of 3-alkyl-2-hydroxyindolines is discussed for both processes. The ring transformation of tetrahydro-3-cyano-2-oxofuro[2,3-b]indoles into dihydro-2-amino-3-carbomethoxyfuro[2,3-b]indoles via ?-lactone imines is also discussed.






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