Synthesis of β‐Trifluoromethylated Δ<sup>1</sup>‐Pyrrolines

Marrec, Olivier; Christophe, Carole; Billard, Thierry; Langlois, Bernard R.; Vors, Jean‐Pierre; Pazenok, S. V.

doi:10.1002/adsc.201000487

Cited by 41 publications

(22 citation statements)

References 21 publications

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“…does not provide the nitro to carbonyl conversion but rather ac omplete reduction to the primary amine. [51] Cyclopentadienone is av ery reactive electrophilic molecule which can be notably stabilized by masking one unsaturation as aD iels-Alder adduct with cyclopentadiene as in bicyclo derivative 79 (Scheme 28). [52] Compound 79 can be profitably used in Michaela dditionsw ith simple nitroalkanesa nd the obtained products 80 then converted into 1,4-dione derivatives 81 by TiCl 3 .T he masked double bondc an be restored by ar etro Diels-Alder reactionu sing the flash vacuump hotolysis methodology (FVP) leading to 4-acylcyclopentenones 82.T he overall process can be consideredasaconjugate addition to the cyclopentenoneunit of an acyl anionequivalent.…”

Section: R Eductive Methodsmentioning

confidence: 99%

The Nitro to Carbonyl Conversion (Nef Reaction): New Perspectives for a Classical Transformation

2015

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This review article reports new procedures and practical application of the nitro to carbonyl conversion that appeared in the literature after our\ud comprehensive report published in 2004. Beside traditional and well explored reactant systems, new procedures including the utilization of molecular oxygen and photoredox catalysis have been introduced for the Nef reaction. Of notable interest is the utilizationof the nitro to carbonyl conversion in tandem and cascade processes aimed at the preparation of hetero and carbocyclic derivatives

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Section: R Eductive Methodsmentioning

confidence: 99%

The Nitro to Carbonyl Conversion (Nef Reaction): New Perspectives for a Classical Transformation

2015

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“…The same route has enabled the synthesis of Δ 1 -pyrrolines of interest apart from tetrapyrrole chemistry. 319 Interestingly, the McMurry–Melton modification of the Nef reaction predates by one year the now more famous McMurry reaction (low-valent titanium-induced radical coupling of two ketones to give the corresponding alkene). 320,321 …”

Section: Development Of De Novo Syntheses Of Gem-dialkylchlorinsmentioning

confidence: 99%

De NovoSynthesis of Gem-Dialkyl Chlorophyll Analogues for Probing and Emulating Our Green World

2015

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Woodward reported his infamous synthesis of chlorin e 6 trimethyl ester, a known synthetic precursor to chlorophyll a. [59][60][61][62][63][64]124 The work was posited on a half-century of intensive studies by many investigators in tetrapyrrole chemistry and began a decade after the close of Fischer's lifetime of research 125−128 (which included an uncompleted synthetic program directed toward chlorophylls 15 ). Indeed, "he read all the umpteen papers on the chlorophylls written by Willstaẗter and Fischer, including the experimental parts." 129 The Woodward synthesis of chlorin e 6 trimethyl ester required 46 steps, of which 24 were spent on converting the sole precursor, Knorr's pyrrole, to the four pyrroles destined to form rings A−D; 7 additional steps accrued to obtain the dipyrromethanes that constitute the Eastern and Western halves (Scheme 13, the step numbers are identical to those shown in ref 64.). The first step formed the Knorr pyrrole (in several kg quantities), the next 24 steps were divided into four parallel paths, whereas the remaining 21 steps proceeded in linear fashion. Remarkable features of the synthesis include the directed intramolecular joining (via an imine) of the Eastern and Western halves (step 33), construction of the acrylate Scheme 10. Hydrogenation of a Porphyrin to Form a Chlorin Scheme 11. Representative meso-Tetraarylchlorins Scheme 12. Methyl Pyropheophorbide a

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“…Recently, the group of Shibata has developed an elegant organocatalyzed asymmetric approach to such pyrrolines [33]. Moreover, an efficient synthesis of β-trifluoromethylated Δ 1 -pyrrolines has been reported [34]. Therefore, we selected pyrrolines with CF 2 R side chains as a second example of 5-membered heterocyclic targets.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of enones, pyrazolines and pyrrolines with gem-difluoroalkyl side chains

Dine¹,

Khalaf²,

Grée³

et al. 2013

Beilstein J. Org. Chem.

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SummaryStarting from easily accessible gem-difluoropropargylic derivatives, a DBU-mediated isomerisation affords enones in fair yields with a gem-difluoroalkyl chain. These derivatives were used to prepare pyrazolines and pyrrolines with the desired gem-difluoroalkyl side chain by cyclocondensations in good yields and with excellent stereoselectivity. A one-pot process was also successfully developed for these sequential reactions. By carrying out various types of Pd-catalyzed coupling reactions for compounds with a p-bromophenyl substituent a route to focused chemical libraries was demonstrated.

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Synthesis of β‐Trifluoromethylated Δ¹‐Pyrrolines

Abstract: -pyrrolines have been easily synthesized in a one-pot procedure from b-(trifluoromethyl)enones. These substrates are valuable building blocks for further syntheses. For example, trifluoromethylated prolines have been obtained.

Cited by 41 publications

References 21 publications

The Nitro to Carbonyl Conversion (Nef Reaction): New Perspectives for a Classical Transformation

The Nitro to Carbonyl Conversion (Nef Reaction): New Perspectives for a Classical Transformation

De NovoSynthesis of Gem-Dialkyl Chlorophyll Analogues for Probing and Emulating Our Green World

Synthesis of enones, pyrazolines and pyrrolines with gem-difluoroalkyl side chains

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Synthesis of β‐Trifluoromethylated Δ1‐Pyrrolines

Abstract: -pyrrolines have been easily synthesized in a one-pot procedure from b-(trifluoromethyl)enones. These substrates are valuable building blocks for further syntheses. For example, trifluoromethylated prolines have been obtained.

Cited by 41 publications

References 21 publications

The Nitro to Carbonyl Conversion (Nef Reaction): New Perspectives for a Classical Transformation

The Nitro to Carbonyl Conversion (Nef Reaction): New Perspectives for a Classical Transformation

De NovoSynthesis of Gem-Dialkyl Chlorophyll Analogues for Probing and Emulating Our Green World

Synthesis of enones, pyrazolines and pyrrolines with gem-difluoroalkyl side chains

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Synthesis of β‐Trifluoromethylated Δ¹‐Pyrrolines