- I2-induced cascade cyclization and dearomatization of indoles for the highly efficient synthesis of iodinated and vinylic spiroindolenines
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The spiroindolenine framework is a privileged heterocyclic motif and is widely present in numerous indole alkaloids. Herein, we develop a metal-free and environmentally friendly approach for the intramolecular cascade cyclization and dearomatization of indole derivatives to selectively afford iodinated and vinylic spiroindolenines by a substrate-controlled strategy. Simple operation, mild conditions, and high yield make this strategy a green and attractive pathway to construct functionalizable spiroindolenine scaffolds, which could be converted into diverse useful spiroindolenine derivatives.
- Li, Yazhou,Liang, Xuewu,Liu, Hong,Liu, Qi,Liu, Xuyi,Wei, Xiaohui,Zhou, Yu
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supporting information
p. 9165 - 9171
(2021/11/23)
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- Rhodium-Catalyzed Enantioselective Cyclization of 3-Allenyl-indoles: Access to Functionalized Tetrahydrocarbazoles
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A highly selective rhodium-catalyzed cyclization of tethered 3-allenylindoles is reported. In a smooth reaction, 1-vinyltetrahydrocarbazoles are obtained in excellent yields and enantioselectivities. Aside from a great functional group tolerance, this method requires neither the Schlenk technique nor the use of anhydrous solvents. Preliminary mechanistic investigations proved that the reaction proceeds via an intermediary formed spiroindolenine which rapidly undergoes an acid-catalyzed stereospecific migration.
- Grugel, Christian P.,Breit, Bernhard
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supporting information
p. 5798 - 5802
(2019/06/08)
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- Rhodium-Catalyzed Diastereo- And Enantioselective Tandem Spirocyclization/Reduction of 3-Allenylindoles: Access to Functionalized Vinylic Spiroindolines
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A highly selective rhodium-catalyzed tandem spirocyclization/reduction of 3-allenylindoles is reported. By employing a Hantzsch ester as reductant, vinylic spiroindolines are obtained in excellent yields as well as diastereo- and enantioselectivity. In addition, the reaction's synthetic utility is highlighted by broad functional group compatibility and exemplified by a gram scale reaction with subsequent assorted transformations.
- Grugel, Christian P.,Breit, Bernhard
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supporting information
p. 9672 - 9676
(2019/12/24)
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- Enantioselective gold-catalyzed allylic alkylation of indoles with ALcohols: An efficient route to functionalized tetrahydrocarbazoles
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[Chemical equation presented] Breaking the taboo: The direct use of allylic alcohols in catalytic and enantioselective Friedel-Crafts alkylation is described for the first time In the presence of chiral gold complexes. This intramolecular Friedel-Crafts reaction was used to prepare a broad range of functionalized tetrahydrocarbazoles (see scheme; X=Me, F, Br, Cl, OMe; R=Me, Et, tBu; R′=H, Me).
- Bandini, Marco,Eichholzer, Astrid
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supporting information; experimental part
p. 9533 - 9537
(2010/03/24)
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