A novel and convenient access to highly substituted spiro[pyrrolidinon-3,3′-indoles]

Synthesis of Substituted 1,2,3,4-Tetrahydro-1-thiacarbazole and Spiro[pyrrolidinone-3,3′-indolinones] through a Common Intermediate Obtained by Condensation of Indolin-2-one, (Aryl)aldehydes, and Meldrum's Acid

“…Since this target adduct was removed from the reaction mixture by crystallization, we turned our attention to our recently described procedure for 2‐substituted indoles,10 in which the corresponding adducts were isolated as stable triethylamine salts.…”

“…We have recently reported a simple synthesis for the preparation of some spiro[pyrrolidinone‐3,3′‐indole] derivatives starting from 2‐substituted indoles, aldehydes, and Meldrum’s acid 10. Continuing our activity in the field of functionalized spirooxindoles, related to horsfiline, we wondered if a similar approach, starting from oxindole‐type trimolecular adducts 8 or 11 , could be used for these purposes.…”

Indole based multicomponent reactions towards functionalized heterocycles

“…40 It is noteworthy that 64 are obtained stricto sensu in tetramolecular reaction processes (Scheme 18). …”

Gold-Catalyzed Synthesis of 2-Sulfenylspiroindolenines via Spirocyclizations

“…Few members of this general class of compounds were previously studied for their structural resemblance with biologically active spirooxindoles, spiroindolenines or spiroindolines [12]. Their synthetic routes were reported mainly via Pummerer reaction [14][15][16], thio-Claisen rearrangement [17], isocyanate trapping [18] or electrophilic activation upon silver catalysis [19]. In this paper we report on the use of novel 2-thiophenyltryptamines in gold(I) promoted cyclization reactions for the synthesis of original 2-thiophenylspiroindolenines.…”