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.
Stereochemical assignment of naturally occurring 2,3-epoxy-2-methylbutanoate esters
Total Syntheses of Five Indole Alkaloids from the Marine Bryozoan Flustra foliacea
Conformational studies on indole alkaloids from Flustra foliacea by NMR and molecular modeling
Regioselective Synthesis of 3-Indolyl(alkoxy)acetates
Cleavage of alkoxycarbonyl protecting groups from carbamates by t-BuNH2
Absolute configuration determination of 2-(2-oxo-3-indolyl)acetamide derivatives
Trapping enols of esters and lactones with diazomethane
Synthesis of Bromoindole Alkaloids from Laurencia brongniartii