Enantioselective <i>N</i>‐Acylation of Biginelli Dihydropyrimidines by Oxidative NHC Catalysis

Brandolese, Arianna; Ragno, Daniele; Leonardi, Costanza; Carmine, Graziano Di; Bortolini, Olga; Risi, Carmela De; Massi, Alessandro

doi:10.1002/ejoc.202000151

Cited by 9 publications

(5 citation statements)

References 90 publications

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“…Different stereoisomers of chiral N-acylated 3,4-dihydropyrimidin-2-(1H)-ones (DHPMs) often exhibit different or even contrary biological activities, thus the synthesis of enantioenriched N-acylated DHPMs has attracted the wide attention of chemists. Massiʼs group [17] realized the asymmetric N-acylation of DHPMs with enals via NHC-catalyzed kinetic resolution (Scheme 11). The method employed a set of mild conditions for the synthesis of Biginelli-type dihydropyrimidines, although in most cases the products were gotten with low to moderate ee values.…”

Section: Kinetic Resolutions Mediated By Acyl Azoliumsmentioning

confidence: 99%

Kinetic Resolutions Enabled by N-Heterocyclic Carbene Catalysis: An Update

Yang,

Fang

2024

Chinese Journal of Organic Chemistry

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Kinetic resolution is one of the most commonly used methods allowing access to enantioenriched compounds. The last two decades have seen the rapid development of kinetic resolutions enabled by N-heterocyclic carbene catalysis, and part of the achievements have been summarized in our previous review paper published in 2017. Since then, a series of new advances have been realized, and this review will provide an update of this field covering reports from mid-2017 to 2023.

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Section: Kinetic Resolutions Mediated By Acyl Azoliumsmentioning

confidence: 99%

Kinetic Resolutions Enabled by N-Heterocyclic Carbene Catalysis: An Update

Yang,

Fang

2024

Chinese Journal of Organic Chemistry

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“…In 2019, Massi and co-workers also tried the reaction conditions on synthesis of polyester oligomers 131 (Scheme 33) [79] and in 2020, for the asymmetric N-acylation of dihydropyrimidines 132. [80] Both experiments utilized air as terminal oxidant in combination with a ETM system, but with poor yields as the outcome (10 % of the polymer 131 and 20 % of the wanted R enantiomer 133).…”

Section: R E V I E W T H E C H E M I C a L R E C O R Dmentioning

confidence: 99%

Aerobic Oxidative N‐Heterocyclic Carbene Catalysis

Stenkvist

Bacaicoa

Goossens

et al. 2023

The Chemical Record

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The ease with which simple starting materials can be transformed into highly functionalized products has made oxidative N‐heterocyclic carbene (NHC) catalysis an area of significant interest. However, the use of stoichiometric amounts of high molecular weight oxidants in most reactions generates an undesired equivalent amount of waste. To address this issue, the use of oxygen as the terminal oxidant in NHC catalysis has been developed. Oxygen is attractive due to its low cost, low molecular weight, and ability to generate water as the sole by‐product. However, molecular oxygen is challenging to use as a reagent in organic synthesis due to its unreactive ground state, which often requires reactions to be run at high temperatures and results in the formation of kinetic side‐products. This review covers the development of aerobic oxidative carbene catalysis, including NHC‐catalyzed reactions with oxygen, strategies for oxygen activation, and selectivity issues under aerobic conditions.

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“…Cinnamaldehydes have been profitably employed as acylating partners of racemic 3,4‐dihydropyrimidin‐2‐(1 H )‐ones (Biginelli dihydropyrimidines, DHPMs) in asymmetric NHC‐catalyzed oxidative reactions, leading access to enantioenriched synthetically and pharmaceutically important N3‐acylated products. [64] Under optimum conditions, pyrrolidine‐based chiral triazolium pre‐catalyst (20 mol%) was used together with n ‐BuLi (2.3 equiv.) and DQ (1.0 equiv.)…”

Section: Acyl/imidoyl Azolium Intermediatesmentioning

confidence: 99%

Oxidative N‐Heterocyclic Carbene Catalysis

Risi

Brandolese

Carmine

et al. 2022

Chemistry A European J

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N-Heterocyclic carbene (NHC) catalysis is a by now consolidated organocatalytic platform for a number of synthetic (asymmetric) transformations via diverse reaction modes/intermediates. In addition to the typical umpolung processes involving acyl anion/homoenolate equivalent species, implementation of protocols under oxidative conditions greatly expands the possibilities of this methodology. Oxidative NHC-catalysis allows for oxidative and oxygenative transformations through specific manipulations of Breslow-type species depending upon the oxidant used (external oxidant or O 2 /air), the derived NHC-bound intermediates paving the way to non-umpolung processes through activation of carbon atoms and heteroatoms. This review is intended to update the state of the art in oxidative NHCcatalyzed reactions that appeared in the literature from 2014 to present, with a strong focus to crucial intermediates and their mechanistic implications.

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Enantioselective N‐Acylation of Biginelli Dihydropyrimidines by Oxidative NHC Catalysis

Cited by 9 publications

References 90 publications

Kinetic Resolutions Enabled by N-Heterocyclic Carbene Catalysis: An Update

Kinetic Resolutions Enabled by N-Heterocyclic Carbene Catalysis: An Update

Aerobic Oxidative N‐Heterocyclic Carbene Catalysis

Oxidative N‐Heterocyclic Carbene Catalysis

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