A new synthesis of tetra-substituted ethylenes

Ireland, C. J.; Pizey, J. S.

doi:10.1039/c39720000004

Cited by 20 publications

(13 citation statements)

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“…trans-1-Methyl-2,3-diphenylaziridine (trans-1a) was prepared from erythro-2-(methylamino)-1,2-diphenylethanol by treatment with Ph 3 P/CCl 4 /Et 3 N, according to a known procedure [19], as well as cis-1a [31] and cis-1,2,3-triphenylaziridine (cis-1b) [32]. Dimethyl dicyanofumarate (DCFM; 7a) was synthesized from methyl cyanoacetate and SOCl 2 [16].…”

Section: Methodsmentioning

confidence: 99%

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Thermal [2+3]‐Cycloadditions of trans‐1‐Methyl‐2,3‐diphenylaziridine with CS and CC Dipolarophiles: An Unexpected Course with Dimethyl Dicyanofumarate

Mlostoń

Urbaniak

Domagała³

et al. 2009

Helvetica Chimica Acta

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The thermal reaction of trans-1-methyl-2,3-diphenylaziridine (trans-1a) with aromatic and cycloaliphatic thioketones 2 in boiling toluene yielded the corresponding cis-2,4-diphenyl-1,3-thiazolidines cis-4 via conrotatory ring opening of trans-1a and a concerted [2 þ 3]-cycloaddition of the intermediate (E,E)-configured azomethine ylide 3a (Scheme 1). The analogous reaction of cis-1a with dimethyl acetylenedicarboxylate (5) gave dimethyl trans-2,5-dihydro-1-methyl-2,5-diphenylpyrrole-3,4-dicarboxylate (trans-6) in accord with orbital-symmetry-controlled reactions (Scheme 2). On the other hand, the reactions of cis-1a and trans-1a with dimethyl dicyanofumarate (7a), as well as that of cis-1a and dimethyl dicyanomaleate (7b), led to mixtures of the same two stereoisomeric dimethyl 3,4-dicyano-1-methyl-2,5-diphenylpyrrolidine-3,4-dicarboxylates 8a and 8b (Scheme 3). This result has to be explained via a stepwise reaction mechanism, in which the intermediate zwitterions 11a and 11b equilibrate (Scheme 6). In contrast, cis-1,2,3-triphenylaziridine (cis-1b) and 7a gave only one stereoisomeric pyrrolidine-3,4-dicarboxylate 10, with the configuration expected on the basis of orbital-symmetry control, i.e., via concerted reaction steps (Scheme 10). The configuration of 8a and 10, as well as that of a derivative of 8b, were established by X-ray crystallography.

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Section: Methodsmentioning

confidence: 99%

“…Unexpectedly, the attempted [2 þ 3]-cycloaddition of cis-1-methyl-2,3-diphenylaziridine (cis-1a; cf. Scheme 1) with the electron-deficient dimethyl dicyanofumarate (DCFM) [16] afforded two stereoisomeric products. The same mixture of products was formed in the reaction of trans-1-methyl-2,3-diphenylaziridine (trans-1a) with DCFM.…”

mentioning

confidence: 99%

Thermal [2+3]‐Cycloadditions of trans‐1‐Methyl‐2,3‐diphenylaziridine with CS and CC Dipolarophiles: An Unexpected Course with Dimethyl Dicyanofumarate

Mlostoń

Urbaniak

Domagała³

et al. 2009

Helvetica Chimica Acta

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“…Dimethyl and diethyl dicyanofumarate (4a,c) were prepared from the corresponding alkyl cyanoacetates by treatment with HCl-free SOCl 2 following a literature protocol [12]. Calculations.…”

Section: General Diethyl Trans-and Cis-1-(4methoxyphenyl)aziridine-2mentioning

confidence: 99%

Concerted vs. Non‐Concerted 1,3‐Dipolar Cycloadditions of Azomethine Ylides to Electron‐Deficient Dialkyl 2,3‐Dicyanobut‐2‐enedioates

Khlebnikov

Konev

Virtsev

et al. 2014

Helvetica Chimica Acta

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The quantum-chemical calculations of the thermal ring opening of 1-methyl-2,3-diphenyl-and 1,2,3-triphenylaziridine with formation of the corresponding azomethine ylides of S-, U-, and W-type as well as their cycloaddition to dimethyl acetylenedicarboxylate (DMAD) and dimethyl 2,3-dicyanobut-2-enedioate, were performed at the DFT B3LYP/6-31G(d) level of theory with the PCM solvation model. The calculations are in complete accordance with experimental results and explain the switch from the concerted to the non-concerted pathway depending on substituents in the dipolarophile and the ylide. It was found that strong electron-withdrawing substituents in dipolarophiles, such as in dialkyl dicyanobutenedioates, significantly reduce the barrier for the formation of zwitterionic intermediates in the reaction of azomethine ylides with such dipoles. This can render the stepwise cycloaddition competitive with the concerted one. However, the concertedness of the cycloaddition even to dipolarophiles with several electron-withdrawing substituents is governed by a fine balance of electronic and steric effects in both ylide and dipolarophile counterparts. The hypothesis that introduction of substituents in the azomethine ylide that destabilize the positive charge in a corresponding zwitterion will favor the concerted cycloaddition even with dialkyl dicyanobutenedioates was tested theoretically and experimentally.

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“…Dimethyl-, diethyl-and diisopropyl dicyanofumarates 1a-1c were prepared from corresponding cyanoacetates by treatment with pure thionyl chloride according to the published general procedure. 12 Attention: reaction could be performed successfully only when the commercial thionyl chloride was purified by distillation over quinoline and linseed oil following the recommended procedure.…”

Section: Methodsmentioning

confidence: 99%

A new approach to morpholin-2-one derivatives via the reaction of β-amino alcohols with dicyanofumarates

Mlostoń¹,

Pieczonka²,

Ali³

et al. 2012

Arkivoc

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A novel approach for the synthesis of morpholin-2-one derivatives from dialkyl dicyanofumarates and β-amino alcohols is presented. The reaction takes place under mild conditions via an addition-elimination-lactonization pathway. The formation of the sixmembered ring occurs selectively leading to a single diastereomer. In contrast to arylhydrazines, the reaction of hydrazine hydrate with dicyanofumarates yields pyrazol-3(2H)-ones and not 5-aminopyrazoles.

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A new synthesis of tetra-substituted ethylenes

Cited by 20 publications

References 1 publication

Thermal [2+3]‐Cycloadditions of trans‐1‐Methyl‐2,3‐diphenylaziridine with CS and CC Dipolarophiles: An Unexpected Course with Dimethyl Dicyanofumarate

Thermal [2+3]‐Cycloadditions of trans‐1‐Methyl‐2,3‐diphenylaziridine with CS and CC Dipolarophiles: An Unexpected Course with Dimethyl Dicyanofumarate

Concerted vs. Non‐Concerted 1,3‐Dipolar Cycloadditions of Azomethine Ylides to Electron‐Deficient Dialkyl 2,3‐Dicyanobut‐2‐enedioates

A new approach to morpholin-2-one derivatives via the reaction of β-amino alcohols with dicyanofumarates

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