Oxindole: A chemical prism carrying plethora of therapeutic benefits

Kaur, Maninder; Singh, Manjinder; Chadha, Navriti

doi:10.1016/j.ejmech.2016.08.011

Cited by 275 publications

(123 citation statements)

References 102 publications

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“…Oxindoles exhibit a wide range of biological activities and have become sought‐after targets in medicinal chemistry . Borylated oxindoles have previously been synthesized by van der Eycken and co‐workers in an achiral fashion .…”

Section: Methodsmentioning

confidence: 99%

Enantioselective Intramolecular Copper‐Catalyzed Borylacylation

et al. 2018

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An enantioselective copper‐catalyzed intramolecular borylacylation is reported. The reaction proceeds through an initial enantioselective borylcupration of the styrene, followed by a nucleophilic attack on the tethered carbamoyl chloride. The products, chiral borylated 3,3‐disubstituted oxindoles, were generated in excellent yields and enantioselectivities. The versatile carbon–boron bond provides a platform for a wide array of diversification.

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Section: Methodsmentioning

confidence: 99%

Enantioselective Intramolecular Copper‐Catalyzed Borylacylation

et al. 2018

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“…Engineering TrpB for activity on 3-methyloxindole 1 would provide biocatalytic access to 3,3-disubstituted oxindoles (Figure 2a), a motif present in a broad range of natural and synthetic biologically active compounds (Figure 2b). [11][12] Various approaches to form 3,3-disubstituted oxindoles have been explored in synthetic chemistry, including C-H activation and chiral catalysts such as phosphoramides or alkaloidderived urea catalysts. [13][14][15] These methods may require protection of the nitrogen and/or activation of C3 and almost always use high chiral catalyst loadings.…”

Section: Introductionmentioning

confidence: 99%

Tailoring Tryptophan Synthase TrpB for Selective Quaternary Carbon Bond Formation

et al. 2019

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We previously engineered the tryptophan synthase b-subunit (TrpB), which catalyzes the condensation reaction between L-serine and indole to form L-tryptophan, to synthesize a range of modified tryptophans from serine and indole derivatives. In this study, we used directed evolution to engineer TrpB to accept 3-substituted oxindoles and form CC bonds leading to new quaternary stereocenters. At first, the TrpBs that could use 3-substituted oxindoles preferentially formed N-C bonds by attacking the oxindole N1 atom. We found, however, that protecting the nitrogen encouraged evolution towards C-alkylation, which persisted even when this protection was removed. After seven rounds of evolution leading to a 400-fold improvement in activity, variant Pfquat efficiently alkylates 3-substituted oxindoles to selectively form new stereocenters at the γ-position of the amino acid products. The configuration of the new γ-stereocenter of one of the products was determined from the crystal structure obtained by microcrystal electron diffraction (MicroED). Substrates structurally related to 3methyloxindole such as lactones and ketones can also be used by the enzyme for quaternary carbon bond formation, where the biocatalyst exhibits excellent regioselectivity for the tertiary carbon atom. Highly thermostable and expressed at > 500 mg/L E. coli culture, TrpB Pfquat provides an efficient and environmentally-friendly platform for the preparation of noncanonical amino acids bearing quaternary carbons.

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“…[11] It is notable that the products are enantioenriched 3,3-disubstituted oxindoles, which are biologically interesting molecules. [12]…”

Section: Two-component Carboboration Involving An Intramolecular Cyclmentioning

confidence: 99%

Transition‐Metal‐Catalyzed 1,2‐Carboboration of Alkenes: Strategies, Mechanisms, and Stereocontrol

Liu

Gao

Zeng

et al. 2019

Israel Journal of Chemistry

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During the past decade, many research groups have described catalytic methods for 1,2-carboboration, allowing access to structurally complex organoboronates from alkenes. Various transition metals, especially copper, palladium, and nickel, have been widely used in these reactions. This review summarizes advances in this field, with a special focus on the catalytic cycles involved in different metal-catalyzed carboboration reactions, as well as the regio-and stereochemical consequences of the underlying mechanisms. 1,2-Carboboration of other unsaturated systems, such as alkynes and allenes, is outside of the scope of this review. Scheme 1. General depiction of catalyst-controlled 1,2-carboboration. In this scheme and throughout the manuscript, nucleophilic reaction partners are drawn in blue, and electrophilic reaction partners are drawn in red. Scheme 4. Cu(I)-catalyzed borylative radical cyclization. Scheme 5. Cu(I)-catalyzed intramolecular carboboration involving an aldol cyclization. Scheme 6. Cu(I)-catalyzed intramolecular acylboration.Review Isr. J. Chem. 2020, 60, 219 -229 Scheme 7. Cu(I)-catalyzed divergent alkylboration of alkenes. Scheme 8. Cu(I)-catalyzed alkene carboboration with aldehydes as the electrophile. Scheme 9. Cu(I)-catalyzed three-component acylboration. Scheme 10. Cu(I)-catalyzed heteroarylboration of 1,3-dienes.

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Oxindole: A chemical prism carrying plethora of therapeutic benefits

Cited by 275 publications

References 102 publications

Enantioselective Intramolecular Copper‐Catalyzed Borylacylation

Enantioselective Intramolecular Copper‐Catalyzed Borylacylation

Tailoring Tryptophan Synthase TrpB for Selective Quaternary Carbon Bond Formation

Transition‐Metal‐Catalyzed 1,2‐Carboboration of Alkenes: Strategies, Mechanisms, and Stereocontrol

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