Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes
- Gianluigi Broggini,
- Egle M. Beccalli,
- Andrea Fasana and
- Silvia Gazzola
Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198
Graphical Abstract
Scheme 1: Typical catalytic cycle for Pd(II)-catalyzed alkenylation of indoles.
Scheme 2: Application of Fujiwara’s reaction to electron-rich heterocycles.
Scheme 3: Regioselective alkenylation of the unprotected indole.
Scheme 4: Plausible mechanism of the selective indole alkenylation, adapted from [49].
Scheme 5: Directing-group control in intermolecular indole alkenylation.
Scheme 6: Direct C–H alkenylation of N-(2-pyridyl)sulfonylindole.
Scheme 7: N-Prenylation of indoles with 2-methyl-2-butene.
Scheme 8: Proposed mechanism of the N-indolyl prenylation.
Scheme 9: Regioselective arylation of indoles by dual C–H functionalization.
Scheme 10: Plausible mechanism of the selective indole arylation.
Scheme 11: Chemoselective cyclization of N-allyl-1H-indole-2-carboxamide derivatives.
Scheme 12: Intramolecular annulations of alkenylindoles.
Scheme 13: A mechanistic probe for intramolecular annulations of alkenylindoles, adapted from Ferreira et al. [66]....
Scheme 14: Asymmetric indole annulations catalyzed by chiral Pd(II) complexes.
Scheme 15: Aerobic Pd(II)-catalyzed endo cyclization and subsequent amide cleavage/ester formation.
Scheme 16: Synthesis of the pyrimido[3,4-a]indole skeleton by intramolecular C-2 alkenylation.
Scheme 17: Synthesis of azepinoindoles by oxidative Heck cyclization.
Scheme 18: Enantioselective synthesis of 4-vinyl-substituted tetrahydro-β-carbolines.
Scheme 19: Pd-catalyzed endo-cyclization of 3-alkenylindoles for the construction of carbazoles.
Scheme 20: Pd-catalyzed hydroamination of 2-indolyl allenamides.
Scheme 21: Amidation reaction of 1-allyl-2-indolecarboxamides.
Scheme 22: Intramolecular cyclization of N-benzoylindole.
Scheme 23: Intramolecular alkenylation/carboxylation of alkenylindoles.
Scheme 24: Intermolecular alkenylation/carboxylation of 2-substituted indoles.
Scheme 25: Mechanistic investigation of the cyclization/carboxylation reaction.
Scheme 26: Plausible catalytic cycle for the cyclization/carboxylation of alkenylindoles, adapted from Liu et ...
Scheme 27: Intramolecular domino reactions of indolylallylamides through alkenylation/halogenation or alkenyla...
Scheme 28: Proposed mechanism for the alkenylation/esterification process through iminium intermediates.
Scheme 29: Cyclization of 3-indolylallylcarboxamides involving 1,2-migration of the acyl group from spiro-inte...
Scheme 30: Domino reactions of 2-indolylallylcarboxamides involving N–H functionalization.
Scheme 31: Cyclization/acyloxylation reaction of 3-alkenylindoles.
Scheme 32: Doubly intramolecular C–H functionalization of a 2-indolylcarboxamide bearing two allylic groups.
