Constructing spirooxindoles from non-oxindole precursors: a one-pot nitro-reduction/double lactamization approach to spiro[indoline-3,3'-quinoline]-2,2'-diones DOI

Raju Chouhan,

Abhijit Gogoi, Sajal Kumar Das

et al.

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: 22(37), P. 7601 - 7606

Published: Jan. 1, 2024

2-(2-Nitrobenzyl)-2-(2-nitrophenyl)malonates, readily prepared by S

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
Dearomative Alkylation-Based Two-Step cis-Diastereoselective Synthesis of Indoline-2,3-Fused Chromans and Tetrahydropyrans DOI

Raju Chouhan,

Nandini Ray,

Nitish Nayan Gogoi

et al.

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 3, 2024

Herein, we describe a two-step,

Language: Английский

Citations

4
HFIP-Mediated Cascade Aminomethylation and Intramolecular Cyclization of Allenamides with N,O-Acetals to Access Tetrahydro-β-carboline Derivatives DOI

Dhananjay Chaudhary,

Chandra Kant Maurya,

Urmila Unnikrishnan

et al.

Chemical Communications, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

A cascade of two C–C bond forming reactions promoted alone by HFIP is described delivering tetrahydro-β-carboline derivatives embedded with an allylic amine functionality.

Language: Английский

Citations

0
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
Switchable Skeletal Rearrangement of Hexahydro-4H-indol-4-ones: Divergent Synthesis of Dihydroxy-4H-cyclopenta[b]pyridin-4-ones and 8-Alkenyl Oxepane-2,6-diones DOI

Zhilai Zhang,

Haifeng Sun,

Mingshuai Zhang

et al.

Organic Letters, Journal Year: 2024, Volume and Issue: 26(20), P. 4205 - 4211

Published: May 14, 2024

An unprecedented base-controlled selective skeletal rearrangement reaction of hexahydro-4

Language: Английский

Citations

3
A Catalytic Intramolecular Aldehyde–Alkyne Metathesis Approach to Azepino[1,2‐a]indoles DOI

U. Deka,

Arup Jyoti Das,

Swapnil Kumar Nath

et al.

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(21), P. 4452 - 4461

Published: July 23, 2024

Abstract Reported herein is a method for the construction of azepino[1,2‐ ]indoles via an intramolecular aldehyde–alkyne metathesis 1‐(5‐aryl‐4‐pentynyl)indole‐2‐carbaldehydes. This Sc(OTf) 3 ‐catalyzed reaction has several remarkable features, such as ready accessibility starting materials, broad substrate scope, operational simplicity, and high yields. The practicality process synthetic potential products were demonstrated with upscaling experiment downstream derivatizations obtained products. We have also extended this methodology to synthesize 6,7‐dihydropyrido[1,2‐ ]indole derivative.

Language: Английский

Citations

3
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
Au(i)/Sc(iii)-co-catalyzed tandem spiroannulation/cycloisomerization of 3-(2-ethynylaryl)-N-tosylaziridines with indoles to access 5H-benzo[b]carbazoles DOI
Wei Wang,

Lan Zheng,

Wenjie Liang

et al.

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: 22(29), P. 5999 - 6003

Published: Jan. 1, 2024

An unusual Au( i )/Sc( iii )-co-catalyzed tandem spiroannulation/cycloisomerization of 3-(2-ethynylaryl)- N -tosylaziridine-2,2-diesters with indoles has been reported. A variety 5 H -benzo[ b ]carbazoles were obtained in moderate to good yields (30–88%).

Language: Английский

Citations

0
Constructing spirooxindoles from non-oxindole precursors: a one-pot nitro-reduction/double lactamization approach to spiro[indoline-3,3'-quinoline]-2,2'-diones DOI

Raju Chouhan,

Abhijit Gogoi, Sajal Kumar Das

et al.

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: 22(37), P. 7601 - 7606

Published: Jan. 1, 2024

2-(2-Nitrobenzyl)-2-(2-nitrophenyl)malonates, readily prepared by S

Language: Английский

Citations

0