Asymmetric organocatalytic synthesis of six-membered oxygenated heterocycles

Núñez, Marta G.; Garcı́a, Pilar Garcı́a; Moro, Rosalina F.; Dı́ez, David

doi:10.1016/j.tet.2009.12.045

Cited by 93 publications

(10 citation statements)

References 104 publications

(65 reference statements)

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“…Given the wealth of THP‐containing products, it is not surprising that several efficient methodologies for the stereoselective construction of variously substituted THPs have been developed throughout the years . Recent examples also include (organo)catalytic methodologies, and 6‐ exo ‐ tet cyclizations of phenylseleno alcohols. [5a] A novel one‐pot multistep synthetic procedure for isochromane derivatives, on the basis of the addition of ortho ‐lithiated aryloxiranes to enaminones, was also reported .…”

Section: Introductionmentioning

confidence: 99%

Toward Customized Tetrahydropyran Derivatives through Regioselective α‐Lithiation and Functionalization of 2‐Phenyltetrahydropyran

et al. 2016

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In this contribution, the first direct and efficient functionalization of the preformed 2-phenyltetrahydropyran (2-PhTHP) nucleus by electrophilic interception of the corresponding α-lithiated derivative by employing sBuLi as the base and THF as the solvent at –78 °C was explored. The presence of N,N,N′,N′-tetramethylethylenediamine (TMEDA) proved to be critical to governing reaction feasibility both in polar and apolar solvents and for improving the yield of the reaction. Both carbon- and heteroatom-based halides were found to be competent electrophiles for this transformation, as well as aliphatic and aromatic aldehydes and ketones, isocyanates, and carboxylic acid derivatives. The combination of hexane/TMEDA lowered the rate of racemization of α-lithiated optically active 2-PhTHP, which thereby enabled calculation of its barrier to inversion at –78 °C

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Section: Introductionmentioning

confidence: 99%

Toward Customized Tetrahydropyran Derivatives through Regioselective α‐Lithiation and Functionalization of 2‐Phenyltetrahydropyran

et al. 2016

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“…Chiral oxygen-containing heterocycles, such as isoxazolines, isoxazolidines [42,43], chromans [44], and dihydrobenzofurans [45], can be found in numerous natural products and biologically active compounds. In particular, the representative Oheterocycles bearing an acetamide or acetate as a side chain are depicted in Fig.…”

Section: The Intramolecular Oxa-michael Addition To αβ-Unsaturated Amentioning

confidence: 99%

Bifunctional Guanidines as Hydrogen-Bond-Donating Catalysts

Kobayashi

Takemoto

2015

Topics in Heterocyclic Chemistry

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Bicyclic guanidines, bearing 2-aminoquinazolin-4-one and 3-aminobenzothiadiazine-1,1-dioxide core structures, work as bifunctional amine catalysts, due to a double hydrogen-bond-donating ability of two guanidine N-H protons, which are capable of activating both nucleophile and electrophile simultaneously. In fact, these guanidine catalysts revealed to promote several asymmetric reactions such as hydrazination of active methylene compounds with azodicarboxylate and 1,3-proton migration of alkynoates to allenoates as well as the oxa-Michael addition and epoxidation of α,β-unsaturated amides and esters with better chemical yields and higher enantioselectivities than the corresponding thioureas. The catalytic mechanisms of these asymmetric reactions and their synthetic applications for biologically active molecules are also discussed in this chapter.

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“…Some of pyran derivatives showed local anesthetization and anti‐arrhythmia activities and can be used as inhibitors of KB (human epidermoid carcinoma K cells) . On the other hand, the chromene skeleton, including that of 2 H ‐chromene and 4 H ‐chromene, is one of the most familiar structural units in naturally occurring compounds with various pharmacological properties such as anticoagulant, anticancer, anti‐anaphylactic, and fungicidal activities . The 2‐amino‐4 H ‐chromenes are rather unusual among the chromene family members .…”

Section: Introductionmentioning

confidence: 99%

An Efficient Green Synthetic Approach to the Synthesis of 4H‐Chromene Compounds under Solvent‐free Conditions

Zaki

Metwally

El‐Ossaily

et al. 2018

Journal of Heterocyclic Chem

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Here, we describe a simple method to synthesize the starting intermediate 2‐amino‐8‐benzylidene‐4‐phenyl‐5,6,7,8‐tetrahydro‐4H‐chromene‐3‐carbonitrile (6) by the reaction of 2,6‐dibenzylidene cyclohexanone with malononitrile in the presence of triethyl amine under solvent‐free conditions. The o‐amino carbonitrile compound 6 was used as a versatile precursor for synthesis of novel heterocyclic compounds fused to the 4H‐chromene ring system heterocycles 7–17 such as chromenopyrimidines, chromenoimidazopyrimidine, chromenopyrimidotriazepinone, and chromenotriazolopyrimidine. The chemical structures of the newly synthesized compounds were established on the basis of elemental and spectral analyses including melting point, thin‐layer chromatography, Fourier transform infrared spectroscopy, 1H‐NMR, and mass spectroscopy, hoping these molecules would allow us to investigate their pharmacological activities in future studies.

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Asymmetric organocatalytic synthesis of six-membered oxygenated heterocycles

Cited by 93 publications

References 104 publications

Toward Customized Tetrahydropyran Derivatives through Regioselective α‐Lithiation and Functionalization of 2‐Phenyltetrahydropyran

Toward Customized Tetrahydropyran Derivatives through Regioselective α‐Lithiation and Functionalization of 2‐Phenyltetrahydropyran

Bifunctional Guanidines as Hydrogen-Bond-Donating Catalysts

An Efficient Green Synthetic Approach to the Synthesis of 4H‐Chromene Compounds under Solvent‐free Conditions

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