Interrupted Plancher Rearrangement Initiated by Dearomative Epoxide–Indole Cyclization: Formal Umpolung Reactivity of Indoles DOI

Raju Chouhan,

Sajal Kumar Das

Organic Letters, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 12, 2024

We herein report the serendipitous discovery of interrupted Plancher rearrangement initiated by an HFIP-promoted dearomative epoxide-indole cyclization, unlocking a new blueprint to formal C3 umpolung reactivity indoles. This rapid complexity generating cascade process paves way toward class fused-bridged indolines in high yields and under full regio- diastereocontrol. The reaction is amenable wide range substituents starting materials.

Language: Английский

C3 versus C5 Regioselectivity in the Intramolecular Dehydrative Friedel–Crafts Alkylation of Indole C4-Tethered Carbinols DOI
Abhijit Gogoi,

Raju Chouhan,

Sajal Kumar Das

et al.

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: March 3, 2025

Described herein is a mild catalytic dehydrative Friedel-Crafts alkylation of 1,1-diarylalkanols─a challenging reaction with exceedingly rare previous success, presumably because the unfavorable steric hindrance around reactive centers and competitive E1 reaction. Executing in an intramolecular fashion benefiting from high nucleophilicity indole, we have successfully utilized this synthesizing 3,4-fused indoles. Interestingly, strategy could also be applied to access 4,5-fused indoles via modification tether connecting alcohol indole moieties.

Language: Английский

Citations

1
Total Syntheses of Uvarindoles A and B, (±)-Pseudophrynaminol, and (±)-Pseudophrynamines 272A and 270 via Dearomative Indole Alkylation DOI

Raju Chouhan,

Sajal Kumar Das

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: March 31, 2025

Herein, we report the first total synthesis of alkaloid uvarindole B with an overall yield 49% over five steps via double C3-alkylation 5-bromoindole, Plancher rearrangement, and Negishi coupling as key steps. We also disclose short syntheses A, pseudophrynaminol, pseudophrynamines 272A 270 dearomative indole alkylation.

Language: Английский

Citations

0
Tandem SNAr/Aldol Condensation of Oxindoles with o-Haloacetophenones Enables Modular Assembly of 2,3-Fused Indolines Bearing a Quaternary Carbon DOI
Zhiping Zheng,

Kai-Heng Yu,

Ziyuan Liu

et al.

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: April 28, 2025

Described herein is a novel base-promoted [4 + 2] annulation reaction of 3-methyl-indolin-2-ones with ortho-haloacetophenones, which enables the modular and reliable synthesis 2,3-fused indolines bearing quaternary carbon. Two C-C bonds can be successively constructed through tandem sequence involving SNAr aldol condensation. This protocol highlighted by transition metal-free conditions, high efficiency, simple operation.

Language: Английский

Citations

0
Interrupted Plancher Rearrangement Initiated by Dearomative Epoxide–Indole Cyclization: Formal Umpolung Reactivity of Indoles DOI

Raju Chouhan,

Sajal Kumar Das

Organic Letters, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 12, 2024

We herein report the serendipitous discovery of interrupted Plancher rearrangement initiated by an HFIP-promoted dearomative epoxide-indole cyclization, unlocking a new blueprint to formal C3 umpolung reactivity indoles. This rapid complexity generating cascade process paves way toward class fused-bridged indolines in high yields and under full regio- diastereocontrol. The reaction is amenable wide range substituents starting materials.

Language: Английский

Citations

1