Diastereoselective Synthesis and Estimation of the Conformational Flexibility of 6-Oxoperhydropyridazine-3-carboxylic Acid Derivatives

Alvarez‐Ibarra, Carlos; Csákÿ, and Aurelio G.; Oliva, Cristina Gómez de la

doi:10.1021/jo0159800

Cited by 19 publications

(7 citation statements)

References 18 publications

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“…The obtained dihydropyridazone 3a was enolized and reacted with iodomethane to give the corresponding α-methyl dihydropyridazone 6 in 82% yield with exclusive diastereoselectivity and without erosion of enantioselectivity (Scheme 3). 18 A plausible catalytic cycle is depicted in Scheme…”

Section: Resultsmentioning

confidence: 99%

N-Heterocyclic carbene-catalyzed [3 + 3] cyclocondensation of bromoenals with hydrazones: highly enantioselective synthesis of dihydropyridazones

et al. 2015

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Section: Resultsmentioning

confidence: 99%

N-Heterocyclic carbene-catalyzed [3 + 3] cyclocondensation of bromoenals with hydrazones: highly enantioselective synthesis of dihydropyridazones

et al. 2015

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“…The title compound was prepared according to the above general procedure from tert -butyl 6-oxo-4,5-dihydropyridazine-3-carboxylate (650 mg, 3.28 mmol, 1 equiv) and NaBH 3 CN (412.2 mg, 6.6 mmol, 2 equiv) in MeOH (16.4 mL, 0.2 M) in 4 h. Flash column chromatography over silica gel (CH 2 Cl 2 /MeOH 97:3 v/v) afforded the title compound as a white powder (353 mg, 54%). mp 109–110 °C.…”

Section: Methodsmentioning

confidence: 99%

The Catalytic Regio- and Stereoselective Synthesis of 1,6-Diazabicyclo[4.3.0]nonane-2,7-diones

et al. 2021

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A straightforward synthesis of original 1,6-diazabicyclo[4.3.0]nonane-2,7-diones was achieved through a DBU-organocatalyzed multicomponent Knoevenagel-aza-Michael-Cyclocondensation (KMC) reaction which takes advantage of an unprecedented highly regio-and diastereoselective conjugate addition of pyridazinones to alkylidene Meldrum's acid intermediates. The key reactive intermediates of this complex process were analyzed by means of electrospray ionization mass spectrometry coupled to ion mobility spectrometry (ESI-IMS-MS) allowing to valid the proposed mechanism.

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“…As ar esult, the cyclization of 3a proceeded smoothly,i nD CE at 70 8 8C, by an isomerization/intramolecular aza-Michael sequence to give 3-(p-tolyamino)-5,6-dihydropyridazin-4(1H)-one (8a)i n6 5% yield after 12 hours.Similarly,the N-aryl 3-amino-5,6-dihydropyridazinone derivatives 8d, 8e,a nd 8g-i were also obtained in good to high yields. [16] To understand the mechanisms for the formation of 3, control experiments were carried out. Theproduct 3n was produced in 80 %y ield when the reaction of 1n with 2a was carried out under an itrogen atmosphere.I nc omparison, no reaction was observed by treating (E)-1-phenyl-2-(p-tolylimino)ethanone with 2a under identical reaction conditions.T hese results indicate that (E)-1-phenyl-2-(ptolylimino)ethanone,w hich could be formed by aerobic oxidation of 1n in the presence of ab ase,i snot involved for the formation of 3n.Furthermore,the 1 HNMR studies of the reaction of a-diazocarbonyls with as eries of bases were conducted to gain information for the formation of 3.T esting the mixture of 2a with either DBU,D BN,D ABCO,o r triethylamine (TEA) at room temperature showed that: 1) the mixture of 2a with TEA or DABCO gave nothing…”

Section: Methodsmentioning

confidence: 99%

Activation of α‐Diazocarbonyls by Organic Catalysts: Diazo Group Acting as a Strong N‐Terminal Electrophile

Chen

et al. 2015

Angewandte Chemie

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Fort he first time a-diazocarbonyls have been used as highly active N-terminal electrophiles in the presence of bicyclic amidine catalysts.The CÀNbond-forming reactions of active methylene compounds as Cnucleophiles with a-diazocarbonyls as N-terminal electrophiles proceed quickly under ambient conditions,i nt he presence of 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU), because of the formation of the reactive N-terminal electrophilic intermediates.DBU activates both the active methylene and a-diazocarbonyl. Importantly, this reaction is general for both active methylenes and adiazocarbonyls,a nd the activation mode will lead to new synthetic applications of a-diazocarbonyls. a-Diazocarbonyls have been known since 1883 for the synthesis of ethyl diazoacetate (EDA), as reported by Curtius, and have attracted increasing interest because of their versatility.[1] These compounds have been extensively studied as metal carbene precursors, [2] 1,3-dipoles, [3] and Cnucleophiles.[4] However,the utility of the electrophilic capability of their terminal nitrogen atom has rarely been studied, save for af ew reports on the use of highly reactive organolithium, Grignard reagents,o ra cyl anion equivalents as Cnucleophiles, [5] and NaH-mediated 1,3-aminoalkylation of a-aminoa-diazoesters to afford tetrasubstituted 1,2,3-triazolines,thus involving an intramolecular amination as the key step. [6] In general, the terminal nitrogen atom of a-diazocarbonyls is much less electrophilic than the neighboring nitrogen atom. [4][5][6][7] Thus,t he intermolecular nucleophilic attack on the terminal nitrogen atom of a-diazocarbonyls,b ya ctive methylenes such as Cnucleophiles,i su nfavored. Recently,F eng and co-workers developed an efficient CÀNb ond-forming reaction, namely,t he a-functionalization of ketones,c atalyzed by a N,N'-dioxide scandium complex, but the reaction is limited to a-alkyl-a-diazoesters.[7] Theoretical calculations at the B3LYP/6-31G* level of theory indicate that the carbonyl oxygen atom of ethyl a-alkyl-a-diazoester coordinates to the strong Lewis acid, Sc(OTf) 3 ,a nd enables the positive charge on the terminal nitrogen atom to increase greatly (Scheme 1a).[7] Herein, we report the first C À Nb ond-forming reaction of active methylenes,a st he Cnucleophiles,w ith various a-diazocarbonyls as N-terminal electrophiles by using DBU as ac atalyst (Scheme 1b). [8,9] In the presence of either DBU or 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), the terminal nitrogen atom of an a-diazocarbonyl turns out to be highly electrophilic,a nd the C À Nb ond-forming reactions can proceed quickly under ambient conditions. As part of our research on carbon-carbon and carbonheteroatom bond-forming reactions, [9,10] we recently developed an efficient a-CÀHf unctionalization reaction of aamino carbonyls for C À Cb ond formation through ab asepromoted intramolecular cross-dehydrogenative coupling (CDC).[11] These results and our interests in the synthetic applications of diazo compounds [12] prompted us to investigate the reactions of ...

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Diastereoselective Synthesis and Estimation of the Conformational Flexibility of 6-Oxoperhydropyridazine-3-carboxylic Acid Derivatives

Cited by 19 publications

References 18 publications

N-Heterocyclic carbene-catalyzed [3 + 3] cyclocondensation of bromoenals with hydrazones: highly enantioselective synthesis of dihydropyridazones

N-Heterocyclic carbene-catalyzed [3 + 3] cyclocondensation of bromoenals with hydrazones: highly enantioselective synthesis of dihydropyridazones

The Catalytic Regio- and Stereoselective Synthesis of 1,6-Diazabicyclo[4.3.0]nonane-2,7-diones

Activation of α‐Diazocarbonyls by Organic Catalysts: Diazo Group Acting as a Strong N‐Terminal Electrophile

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