Base-Catalyzed Condensation of 2-Hydroxybenzaldehydes with α,β-Unsaturated Aldehydes - Scope and Limitations

Lesch, B.; Toräng, Jakob; Vanderheiden, Sylvia; Bräse, Stefan

doi:10.1002/adsc.200404239

Cited by 65 publications

(22 citation statements)

References 37 publications

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“…Reaction path a: synthesis of 2,2-dimethyl-2H-chromene-3-carbaldehydes 3 and 9-methyl-8,12-dioxatricyclo [7.3.1.0 2,7 ]trideca-2,4,6-trien-11-ols 4. [15] Reaction path b: preliminary synthesis of coumarin 6d-H.…”

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“…[15] The reactions, depicted in pathway a, Scheme 1, were performed in mixtures of dioxane and water. Upon screening for new conditions for the base-catalyzed condensation of salicylaldehydes with α,β-unsaturated aldehydes, we observed that a new product -a coumarinwas formed if the reactions were carried out in ionic liquids with 2-hydroxy-6-methoxy-4-methylbenzaldehyde (1d) and acrolein (5a) (pathway b, Scheme 1).…”

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confidence: 99%

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Synthesis of 3‐Alkylcoumarins from Salicylaldehydes and α,β‐Unsaturated Aldehydes Utilizing Nucleophilic Carbenes: A New Umpoled Domino Reaction

et al. 2007

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Keywords: Coumarins / Ionic liquids / N-heterocyclic carbene (NHC) / Domino reaction / UmpolungStarting from salicylaldehydes and α,β-unsaturated aldehydes, a new coumarin synthesis in ionic liquids is presented. The key feature is the generation of N-heterocyclic carbenes (NHC) and an Umpolung reaction.During the last decade, N-heterocyclic carbenes (NHCs) have been successfully introduced as ligands for transitionmetal catalysis [1] and recently NHCs have been effectively applied as organocatalysts [2] in a large number of chemical transformations, including transesterification/acylation, [3] benzoin [4] and Stetter [5] reactions. The generation of homoenolate equivalents, by NHC-catalyzed Umpolung of α,β-unsaturated aldehydes, was independently described by Glorius [6] and Bode [7] in the synthesis of γ-butyrolactones. Subsequently, this methodology has been extended towards the synthesis of β-lactones, [8] spiro γ-butyrolactones, [9] γ-lactams [10] and to redox esterification of α,β-unsaturated alScheme 1. Reaction path a: synthesis of 2,2-dimethyl-2H-chromene-3-carbaldehydes 3 and 9-methyl-8,12-dioxatricyclo[7.3.1.0 2,7 ]trideca-2,4,6-trien-11-ols 4.[15] Reaction path b: preliminary synthesis of coumarin 6d-H.[a]

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Synthesis of 3‐Alkylcoumarins from Salicylaldehydes and α,β‐Unsaturated Aldehydes Utilizing Nucleophilic Carbenes: A New Umpoled Domino Reaction

et al. 2007

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“…Similar observations have been reported for the analogous condensation of salicylic aldehydes with prenal. [24] The ratio of the oxa-Michael product to the competitively formed aldol reaction product was shifted in favor of the latter with increasing basicity of the base. Additionally, the usage of a weaker base should also enhance the stability of 4-hydroxycyclohexenones such as 10g and 13b during the condensation reaction.…”

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The Domino Oxa‐Michael Addition–Aldol Reaction: Access to Variably Substituted Tetrahydroxanthenones

et al. 2006

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Tetrahydroxanthenones represent the core of many natural products, most of which exhibit interesting biological activities. In the course of our synthetic efforts towards the total synthesis of the secalonic acids, which contain two of these tricyclic units, we have investigated the influence of substituents on the one‐step domino oxa‐Michael addition–aldol reaction leading to tetrahydroxanthenones. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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“…For example, the N-methylation of indoles, the condensations of unsaturated aldehydes or ketones and the simple additions of alkyne [27,28,[42][43][44][45][46][47][48][49] To sum up, DABCO, as a small organic molecular catalyst has an important place in organic synthesis. Compared with the traditional transition-metal catalysts, DABCO is a widely used reagent which is stable, contamination-free, convenient and cheap.…”

Section: Application Of Dabco In Other Organic Synthesis Reactionsmentioning

confidence: 99%

Organic reactions catalyzed by 1, 4-diazabicyclo [2.2.2] octane (DABCO)

Yang

Tian

2008

Front. Chem. China

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The organic reactions catalyzed by 1, 4-diazabicyclo [2.2.2] octane (DABCO) are reviewed. Most of the reactions start conveniently from available substrate and proceed under mild conditions. The reactions are environmentally friendly and the catalyst can be recycled in some cases. The perspectives on DABCO-catalyzed reactions are pointed out. Keywords 1, 4-diazabicyclo [2.2.2] octane (DABCO), organic synthesis, catalysis 1,4-Diazabicyclo [2.2.2] octane (DABCO, Scheme 1), a cage-like compound, is a small diazabicyclic molecule, which has weak alkalescence, medium-hindrance and widely used in organic synthesis reactions. On the one hand, it can serve as a weak base and ligand, for example, reactions of the Nmethylation of indoles and Pd(OAc) 2 /DABCO-catalyzed Stille cross-coupling reaction, etc. On the other hand, it is also a very widely used catalyst in organic synthesis reactions, for example, the Baylis-Hillman reaction, synthesis of three-membered carbocyclic compounds and heterocyclic reactions containing oxygen, nitrogen. According to the types of products, this paper introduces the application of DABCO in organic synthesis in the recent years.

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Base-Catalyzed Condensation of 2-Hydroxybenzaldehydes with α,β-Unsaturated Aldehydes - Scope and Limitations

Cited by 65 publications

References 37 publications

Synthesis of 3‐Alkylcoumarins from Salicylaldehydes and α,β‐Unsaturated Aldehydes Utilizing Nucleophilic Carbenes: A New Umpoled Domino Reaction

Synthesis of 3‐Alkylcoumarins from Salicylaldehydes and α,β‐Unsaturated Aldehydes Utilizing Nucleophilic Carbenes: A New Umpoled Domino Reaction

The Domino Oxa‐Michael Addition–Aldol Reaction: Access to Variably Substituted Tetrahydroxanthenones

Organic reactions catalyzed by 1, 4-diazabicyclo [2.2.2] octane (DABCO)

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