Furano- and pyrano-idolines-model compounds for indole alkaloid studies

Reactivity of tetrahydrochromeno[2,3‐b]indoles: chromic indicators of cyanide

“…The synthesis of tetrahydrochromeno[2,3‐ b ]indole ( CR ) involves the stoichiometric reaction of 2‐hydroxy‐5‐nitrobenzyl bromide with an N ‐methyl‐2,3‐disubstituted indole ( 1a , 1b , 1c , 1d , 1e ) to afford CR 2a , 2b , 2c , 2d , 2e (Scheme ). The synthesis of CR 2a was reported by Spande and co‐workers in a study of Koshland's reagent; however, detailed characterization was not performed. Although not directly related to CR synthesis, the literature contains reports of similarly fused ring systems .…”

The Catalytic Asymmetric Fischer Indolization

“…The use of simple α-branched carbonyl compounds, for instance, leads to the formation of indolenines bearing a quaternary stereocenter . In cases where a suitable internal nucleophile or electrophile is tethered to the α-branched carbonyl compound, chiral annulated indolines are obtained . This strategy was elaborated by Nishida et al who developed a chiral auxiliary-based route to give pyrroloindolines with up to 85:15 dr. More recently, Garg and co-workers applied the same auxiliary to their interrupted Fischer indolization to access an enantiomerically enriched furoindoline .…”

Mechanistic Dichotomy with Alkynes in the Formal Hydrohydrazination/Fischer Indolization Tandem Reaction Catalyzed by a Ph3PAuNTf2/pTSA Binary System

“…3‐(2‐Methyl‐1 H ‐3‐indolyl)‐1‐propanol (3p): 30 Yield 62 mg (92 %); viscous oil; R f = 0.52 (hexane/EtOAc, 60:40). 1 H NMR (300 MHz, CDCl 3 ): δ = 7.65 (br.…”

“…1 [28] Yield 51 mg (82 %); viscous oil; R f = 0.80 (hexane/EtOAc, 90:10). 1 [29] Yield 70 mg (89 %); viscous oil; R f = 0.76 (hexane/EtOAc, 90:10 [30] [31] [32] [33] [34]…”