Some reactions of lithium .alpha.-lithiocyclopropanecarboxylate

Warner, Philip; Le, Diem Duy

doi:10.1021/jo00344a030

Cited by 27 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…in THF and trimethylsilyl chloride. 333 Scheme 139. Stereochemistry of the products resulting from the metalation/protonation of methyl chrysanthemate under kinetically controlled conditions.…”

Section: Reactions Implying the Metalation Of Alkyl Chrysanthematesmentioning

confidence: 99%

Pyrethroid insecticides Chapter IVa. Reactivity of chrysanthemic acid and its lower esters

Krief¹

2022

Arkivoc

View full text Add to dashboard Cite

The reactivity of chrysanthemic acid and of its "lower esters" (methyl, ethyl, isopropyl and t-butyl) has played a crucial role in their structure elucidation, the discovery of new insecticides and in the understanding of their environmental fate.The reactivity of the carboxylic acid moiety and of its esters, that of the isobutenyl moiety and that of the cyclopropane ring are orthogonal to each other. The fact that this compound class is of relevance for industry has increased the diversity of the reactions disclosed especially that in the patented literature that associates science and economy and is at the roots of the green chemistry.

show abstract

Section: Reactions Implying the Metalation Of Alkyl Chrysanthematesmentioning

confidence: 99%

Pyrethroid insecticides Chapter IVa. Reactivity of chrysanthemic acid and its lower esters

Krief¹

2022

Arkivoc

View full text Add to dashboard Cite

show abstract

“…I-Allylcyclopropanemethclnol (20 (22). FC (Et20) followed by bulb-to-bulb distillation gave 72 % of 22 as a colorless liquid, b. p. 90"/0.05Torr.…”

Section: 6-di(tert-buty/)-4-methylphenyl I-hydrox~~cyclopropune~urbmentioning

confidence: 99%

“…Similarly, attempts to nitrate the dilithio derivative of cyclopropane carboxylic acid [22] or the enolate of the tert-butylthio ester [20] [21] failed. We found, however, that another lithiated cyclopropane carboxylate can be nitrated in good yield and can be used for reactions with electrophiles quite generally: the BHT ester 6 (see Scheme 6) which we have originally employed for in situ generation of cyclopropylidene ketene [25].…”

mentioning

confidence: 99%

ChemInform Abstract: Generation and Reactions of Lithiated tert. Butyl and 2,6‐Di(tert‐butyl)‐4‐methylphenyl Cyclopropane Carboxylates.

1987

View full text Add to dashboard Cite

(14.VI1.86) trrf-Butyl and 2,6-di(tert-butyl)-4-methylphenyl (RHT) cyclopropanecarboxylates (4, 6, 24, 25) are lithiated with LiN(i-Pr), and t -BuLi, respectively. Reactions with alkyl halides, aldehydes, acyl chlorides, and heteroelectrophiles give a-substituted BHT esters which can be cleaved (t-BuOK/H,O/THF) to the corresponding carboxylic acids or reduced (LiAIH,/THF) to the cyclopropdnemethanols.Though cyclopropane (la) itself is more acidic than the less strained cycloalkanes and open-chain alkanes (cf. lb) [l] [2], the relative acidity of the corresponding derivatives with conjugatively electron-withdrawing groups (EWG) may be reversed (2a less acidic than 2b), as shown by many mechanistic investigations with various EWG's (COR [3- [ll]). This effect is normally ascribed to the increase in strain upon introduction of a trigonal center into a three-membered ring [12] (compare 3a with 3b). Pyramidalized carbanion centers or C-atom rather than heteroatom-metalated structures (compare 3a with 3c) are, therefore, discussed for such species3). Alternatively, the carbanionoid species can be stabilized by decoupling to a diradical, see 3d [17] [18]. Hitherto, it was not possible to isolate suitable single crystals for X-ray structure analysis to obtain insight about the bonding in such species.Besides these physical organic aspects, synthetic applications of EWG-substituted cyclopropyl nucleophiles have been studied extensively. A list of leading references to papers in which the successful generation and reactions with electrophiles of metalated ') , ) 3,Part of the projected Ph. D. thesis of R . H . , ETH Zurich.Part of the Master's thesis of Th.M.. ETH Zurich, 1985. For the question as to whether a pyramidal ketonic carbanion exists or not, see [13-161.

show abstract

“…DaR auch elektrostatische Abstohng die Selbstaddition verhindern kann, zeigt die kiirzlich publizierte Arbeit 17) iiber zweifach lithiierte Cyclopropancarbonsaure 22-2 Li. Hier wurden bei schlechtem Umsatz die substituierten Carbonsauren 22-El gebildet.…”

Section: B Deprotonierungs-alkylierungsversucheunclassified

Deprotonierung und diastereoselektive Alkylierung von Cyclopropancarbonsäure‐methylestern

Reichelt

Reißig

1983

Chem. Ber.

View full text Add to dashboard Cite

Anhand von Modellen wird gezeigt und erklart, in welchen Fallen bei der Deprotonierung vonCyclopropancarbonsaure-methylestern Esterkondensation eintritt und in welchen Alkylierung des Esterenolats moglich ist. Unter bestimmten strukturellen Voraussetzungen (sterische und elektronische Effekte) sind die entsprechenden 1-alkylierten Derivate in hoher Ausbeute und mit maRiger bis guter Diastereoselektivitat zuganglich. Die Isomerenverhaltnisse werden bei 2-alkylund 2-arylsubstituierten Cyclopropancarbonestern hauptsachlich von den sterischen Gegebenheiten bestimmt , wahrend 2-Alkoxycyclopropane, wie von uns bereits fur Siloxycyclopropane beschrieben, teilweise kontrasterisch alkyliert werden. Der EinfluR von Elektrophil und Reaktionsbedingungen auf die Diastereoselektivitat wird gepruft und diskutiert. Deprotonation and Diastereoselective Alkylation of Methyl CyclopropanecarboxylatesUsing model compounds it is demonstrated when deprotonation of methyl cyclopropanecarboxylates leads to ester condensation products and when alkylation of the ester enolate can be performed. Under certain structural conditions (steric and electronic effects) the corresponding I-alkylated derivatives are obtainable in high yield and with moderate to good diastereoselectivity. For 2-alkyl-or 2-aryl-substituted methyl cyclopropanecarboxylates the ratio of isomers is governed mainly by steric effects, while 2-alkoxycyclopropanes are in part alkylated contrasterically, as we have already described for the siloxy-substituted case. The influence of electrophile and reaction conditions on the diastereoselectivity is investigated and discussed.

show abstract

Some reactions of lithium .alpha.-lithiocyclopropanecarboxylate

Cited by 27 publications

References 0 publications

Pyrethroid insecticides Chapter IVa. Reactivity of chrysanthemic acid and its lower esters

Pyrethroid insecticides Chapter IVa. Reactivity of chrysanthemic acid and its lower esters

ChemInform Abstract: Generation and Reactions of Lithiated tert. Butyl and 2,6‐Di(tert‐butyl)‐4‐methylphenyl Cyclopropane Carboxylates.

Deprotonierung und diastereoselektive Alkylierung von Cyclopropancarbonsäure‐methylestern

Contact Info

Product

Resources

About