Advances in Catalytic Asymmetric Dearomatization

ACS Central Science, Journal Year: 2021, Volume and Issue: 7(3), P. 432 - 444

Published: Feb. 22, 2021

Asymmetric catalysis has been recognized as the most enabling strategy for accessing chiral molecules in enantioenriched forms. Catalytic asymmetric dearomatization is an emerging and dynamic research subject catalysis, which received considerable attention recent years. The direct transformations from readily available aromatic feedstocks to structurally diverse three-dimensional polycyclic make catalytic reactions of broad interest both organic synthesis medicinal chemistry. However, inherent difficulty disruption aromaticity demands a large energy input during process, might be incompatible with conditions generally required by catalysis. In this Outlook, we will discuss representative strategies examples various compounds try convince readers that overcoming above obstacles, could advance chemical sciences many respects.

Language: Английский

Ag-Catalyzed Asymmetric Interrupted Barton–Zard Reaction Enabling the Enantioselective Dearomatization of 2- and 3-Nitroindoles

Organic Letters, Journal Year: 2022, Volume and Issue: 24(3), P. 826 - 831

Published: Jan. 14, 2022

We disclose a Ag-catalyzed asymmetric interrupted Barton–Zard reaction of α-aryl-substituted isocyanoacetates with 2- and 3-nitroindoles, which enables the dearomatization nitroindoles hence offers rapid access to an array optically active tetrahydropyrrolo[3,4-b]indole derivatives bearing three contiguous stereogenic centers, including two tetrasubstituted chiral carbon atoms pretty outcomes (up 99% yield, 91:9 dr, 96% ee). The synthetic potential protocol was showcased by gram-scale versatile transformations product.

Language: Английский

Enantioselective Synthesis of Fused Polycyclic Tropanes via Dearomative [3 + 2] Cycloaddition Reactions of 2-Nitrobenzofurans

Organic Letters, Journal Year: 2019, Volume and Issue: 22(1), P. 164 - 167

Published: Dec. 23, 2019

A straight synthetic approach to fused polycyclic tropane scaffold formation through an asymmetric dearomatization cycloaddition process of 2-nitrobenzofurans with cyclic azomethine ylides was successfully developed. In the presence a chiral copper complex, derived from Cu(OAc)2 and diphosphine ligand, series derivatives were obtained in high yields (75–91%) excellent enantioselectivities (90–98%). The utility this method showcased by facile transformation product.

Language: Английский

Recent Dearomatization Strategies of Benzofurans and Benzothiophenes

Asian Journal of Organic Chemistry, Journal Year: 2021, Volume and Issue: 10(5), P. 932 - 948

Published: March 10, 2021

Abstract This review article discusses about the recent developments in area of strategies for dearomatization benzofurans and benzothiophenes (2010–2020). The readers can understand current state art this intriguingly important organic synthesis generation diversely functionalized molecules, polycyclic systems from highly abundant benzothiophenes. We hope that would help synthetic community design development new as well further growth novel rapidly growing research.

Language: Английский

Recent Advances in Synthetic Strategies to 2,3-Dihydrobenzofurans

Synthesis, Journal Year: 2020, Volume and Issue: 52(10), P. 1451 - 1477

Published: March 16, 2020

This review gives an overview on recent developments in methods for the construction of compounds with 2,3-dihydrobenzo­furan core period 2012 to 2019. Interest 2,3-dihydrobenzofurans is constantly increasing. The are divided into intermolecular and intramolecular approaches. Intermolecular approaches subdivided according parent intermediate key reaction, while by which bond formed reaction. transformation benzofurans dihydrobenzofurans other miscellaneous also discussed. Approaches useful synthesis natural products emphasized. 1 Introduction 2 2.1 o-Quinone Methides o-Quinones 2.2 p-Quinone p-Quinones 2.3 Nitrogen-Containing Phenols Quinones 2.4 o-Hydroxyphenylcarbonyl Derivatives 2.5 Miscellaneous 3 Intramolecular 3.1 O–C2 Bond Forming 3.2 C2–C3 3.3 C3–Aryl 3.4 O–Aryl 4 From BF DHB 5 Rearrangements Aromatizations

Language: Английский

Catalytic asymmetric dearomative [4 + 2] annulation of 2-nitrobenzofurans and 5H-thiazol-4-ones: stereoselective construction of dihydrobenzofuran-bridged polycyclic skeletons

Organic Chemistry Frontiers, Journal Year: 2021, Volume and Issue: 8(22), P. 6330 - 6336

Published: Jan. 1, 2021

An organocatalytic asymmetric dearomative [4 + 2] annulation of 2-nitrobenzofurans and 5 H -thiazol-4-ones is developed for the construction dihydrobenzofuran-bridged polycyclic skeletons with good results.

Language: Английский

Organocatalytic Regio- and Enantioselective [3 + 2]-Annulations of Ninhydrin-Derived Morita–Baylis–Hillman Carbonates with 3-Methyleneoxindoles

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 87(5), P. 3184 - 3194

Published: Feb. 8, 2022

A type of Morita-Baylis-Hillman (MBH) carbonates has been developed from ninhydrin. These MBH have successfully employed as 3C-synthons in the organocatalytic asymmetric [3 + 2]-annulations isatin-derived electron-deficient olefins, affording structurally diverse spirooxindoles high yield with excellent stereoselectivity. In particular, regioselectivity was controlled by reaction partner, 3-methyleneoxindoles carbonyl groups (R = ArCO), β-selective products and ester CO2Me) furnishing γ-selective products. The representative scale-up reactions transformation product were examined. mechanism expounded control experiments.

Language: Английский

Dearomatization of 3‐Nitroindoles with Highly γ‐Functionalized Allenoates in Formal (3+2) Cycloadditions

Chemistry - A European Journal, Journal Year: 2019, Volume and Issue: 25(60), P. 13688 - 13693

Published: Sept. 11, 2019

3-Nitroindoles are easily reacted with highly substituted γ-allenoates in the presence of a commercially available phosphine catalyst. For instance, allenoates derived from biomolecules such as amino and deoxycholic acids combined for first time 3-nitroindole. The corresponding dearomatized (3+2) tricyclic cycloadducts obtained α-regioisomers exclusively. DFT computations shed light on this multi-step reaction mechanism selectivities observed sequence.

Language: Английский

Asymmetric dearomatization of 2-nitrobenzofurans by organocatalyzed one-step Michael addition to access 3,3′-disubstituted oxindoles

Chemical Communications, Journal Year: 2020, Volume and Issue: 56(17), P. 2586 - 2589

Published: Jan. 1, 2020

An efficient enantioselective dearomatization of 2-nitrobenzofurans was realized via an organocatalyzed one-step Michael addition process. This method provides a facile strategy to access range structurally diverse 3,3'-disubstituted oxindoles, which feature intriguing combination two privileged motifs including 3-pyrrolyl-substituted-oxindoles and 2,3-dihydrobenzofurans substructures, in excellent results.

Language: Английский

Optically Active Flavaglines-Inspired Molecules by a Palladium-Catalyzed Decarboxylative Dearomative Asymmetric Allylic Alkylation

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(28), P. 12039 - 12045

Published: June 25, 2020

With the aid of a class newly discovered Trost-type bisphosphine ligands bearing chiral cycloalkane framework, Pd-catalyzed decarboxylative dearomative asymmetric allylic alkylation (AAA) benzofurans was achieved with high efficiency [0.2–1.0 mol% Pd2(dba)3/L], good generality, and enantioselectivity (>30 examples, 82–99% yield 90–96% ee). Moreover, diversity-oriented synthesis (DOS) previously unreachable flavaglines is disclosed. It features reliable scalable sequence freshly developed Tsuji–Trost–Stoltz AAA, Wacker–Grubbs–Stoltz oxidation, an intra-benzoin condensation, conjugate addition, which allows efficient construction challenging compact cyclopenta[b]benzofuran scaffold contiguous stereocenters. This strategy offers new avenue for developing flavagline-based drugs.

Language: Английский