BINOL-phosphoric acid catalyzed asymmetric Mannich addition of β-ketoesters to indolenines generated in situ by DDQ

Ramesh, B.; Kumar, Gulshan; Yarlagadda, Suresh; Sridhar, Balasubramanian; Reddy, B. V. Subba

doi:10.1016/j.tet.2019.130620

Cited by 7 publications

(6 citation statements)

References 54 publications

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“…More recently, Reddy's group reported the ( R )- BPA10 -catalysed enantioselective Mannich addition of β-keto esters 14 to in situ generated indolenines (Scheme 5). 57 They used both cyclic and non-cyclic keto esters successfully in order to obtain α-amino acid derivatives 15 , bearing at least one chiral tetrasubstituted carbon, in good yields (56–87%). Even though the enantiocontrol of the reaction was highly dependent on the substituents (26–98% ee), the diastereomeric ratio was found to be above 9 : 1 in all cases.…”

Section: Enantioselective Nucleophilic Additions To Cn Bondsmentioning

confidence: 99%

An overview of the applications of chiral phosphoric acid organocatalysts in enantioselective additions to CO and CN bonds

et al. 2022

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Section: Enantioselective Nucleophilic Additions To Cn Bondsmentioning

confidence: 99%

An overview of the applications of chiral phosphoric acid organocatalysts in enantioselective additions to CO and CN bonds

et al. 2022

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“…Finally, 6‐methyl‐2‐phenyl‐1 H ‐indole ( 1 d ) and 2‐(4‐methoxyphenyl)‐1 H ‐indole ( 1 l ) were also successfully reacted with butanone, respectively, affording corresponding products ( 3 ai , 3 aj ). The absolute configurations of all products were determined by comparison with previously reported chiral HPLC analyses [33–36, 42] …”

Section: Resultsmentioning

confidence: 99%

“…The absolute configurations of all products were determined by comparison with previously reported chiral HPLC analyses. [33][34][35][36]42] In order to understand the mechanism of the reaction, a series of experiments were performed. First, to verify the presence of radicals in the reaction process, the radical scavenger butylated hydroxytoluene (BHT) was used in the [a] Unless otherwise noted, reaction conditions: 1 (0.3 mmol, 1.0 equiv), 2 (9.0 mmol, 30.0 equiv), WGL (90 mg, 720 U, 0.21 mol %), ACT (7 mg, 0.03 mmol, 10 mol %), n-Bu 4 NPF 6 (117 mg, 0.3 mmol, 1.0 equiv) and deionized water (0.12 mL) in DMF (6.0 mL) under a constant current of 1 mA in an undivided cell with two platinum sheet electrodes (each 15 mm × 10 mm × 0.…”

Section: Resultsmentioning

confidence: 99%

Merging the Non‐Natural Catalytic Activity of Lipase and Electrosynthesis: Asymmetric Oxidative Cross‐Coupling of Secondary Amines with Ketones

et al. 2022

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We describe the enantioselective oxidative cross-coupling of secondary amines with ketones by combining the non-natural catalytic activity of lipase with electrosynthesis. Various 2,2-disubstituted 3-carbonyl indoles with a stereogenic quaternary carbon center were synthesized from 2-substituted indoles in yields up to 78 % with good enantioand diastereoselectivities (up to 96 : 4 e.r. and > 20 : 1 d.r.). This unprecedented protocol demonstrated that hydrolase catalysis is compatible with electrosynthesis, and the reaction can be carried out in organic solvents with a broad substrate scope and good stereoselectivity. This work provides insights into enzymatic electrosynthesis.

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“…In addition, the reactivity of 2‐indanone‐1‐carboxylate was examined, although, the corresponding product was obtained in low yield and low selectivity in comparison with 1‐indanone‐2‐carboxylates (Scheme 49). [85] …”

Section: Organocatalyzed Asymmetric Mannich Reactionmentioning

confidence: 99%

Organocatalyzed Asymmetric Mannich Reaction: An Update

et al. 2021

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The Mannich reaction is a multicomponent reaction resulting in aminoalkylation of an acidic proton placed next to a carbonyl functional group. It involves an appropriate carbonyl compound, such as formaldehyde and a primary or secondary amine or ammonia. The final product is a β‐amino‐carbonyl compound known as a Mannich base. Reactions between aldimines and α‐methylene carbonyls are also considered as Mannich reaction since these imines are generated from the reaction of amines and aldehydes. It comprises the reaction of primary or secondary amines or ammonia, formaldehyde and appropriate α‐CH‐acidic compounds (nucleophiles) such as carbonyl compounds having α‐CH‐acidic, nitriles, acetylenes, aliphatic nitro compounds, α‐alkyl‐pyridines or imines. Owing to the development of asymmetric organocatalysis, reports on asymmetric Mannich reaction have been drastically increased. The asymmetric Mannich reaction offers access to enantioenriched β‐amino ketones or β‐amino aldehydes, which are present as a scaffold in several natural products. Organocatalysts have been developed not only as a supplement to metal‐catalyzed reactions or to biocatalysis, but nowadays, they are extensively used for the synthesis of various optically pure compounds that could not be achieved via metal‐ or biocatalyzed reactions. In this review, we try to update the advances in organocatalyzed asymmetric Mannich reactions, covering the recent advances of the subject from 2008 to date.

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BINOL-phosphoric acid catalyzed asymmetric Mannich addition of β-ketoesters to indolenines generated in situ by DDQ

Cited by 7 publications

References 54 publications

An overview of the applications of chiral phosphoric acid organocatalysts in enantioselective additions to CO and CN bonds

An overview of the applications of chiral phosphoric acid organocatalysts in enantioselective additions to CO and CN bonds

Merging the Non‐Natural Catalytic Activity of Lipase and Electrosynthesis: Asymmetric Oxidative Cross‐Coupling of Secondary Amines with Ketones

Organocatalyzed Asymmetric Mannich Reaction: An Update

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