Stereoselectivity of catalytic cyclopropanation reactions. Catalyst dependence in reactions of ethyl diazoacetate with alkenes

Doyle, Michael P.; Dorow, Roberta L.; Buhro, William E.; Griffin, John H.; TAMBLYN, W. H.; Trudell, Mark L.

doi:10.1021/om00079a010

Cited by 129 publications

(36 citation statements)

References 2 publications

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“…It was synthesized independently to determine its reactivity with ethyl vinyl ether and its behaviour in the presence of rhodium(I1) acetate and to establish with certainty that neither dihydrofuran 43 nor oxetane 48 were formed from the ketene. Diphenylketene (20) was prepared from acid chloride 52 upon treatment with triethylamine (Scheme 8) (14). For the thermal reaction a solution of diphenyl ketene (20) and ethyl vinyl ether in freshly distilled ether was stirred overnight under argon.…”

Section: Resultsmentioning

confidence: 99%

“…Diphenylketene (20) was prepared from acid chloride 52 upon treatment with triethylamine (Scheme 8) (14). For the thermal reaction a solution of diphenyl ketene (20) and ethyl vinyl ether in freshly distilled ether was stirred overnight under argon. Cyclobutanone 44 was obtained in 88% yield (IR, 1779 cm-').…”

Section: Resultsmentioning

confidence: 99%

“…The dihydrofuran may arise from a concerted or stepwise dipolar cycloaddition to the en01 ether or, alternatively, the ethoxy-substituted cyclopropylketone is a true intermediate that undergoes rapid fragmentation and subsequent ring closure to the dihydrofuran. Doyle et al (20) have examined cyclopropanations with ethyl diazoacetate. The regio-and stereochemical control in catalytic cyclopropanation reactions is derived from the transition metal, its associated ligands, the diazo compound, and the olefin.…”

Section: Discussionmentioning

confidence: 99%

“…by Doyle et al (6,20,25) to occur through an initial interaction between the olefinic T bond and the electrophilic centre of the metal carbenoid, followed by a-bond formation with backside displacement of the catalyst (Scheme 10). As the reaction proceeds the T-complexed olefin may rotate around the electrophilic centre to place the C-C bond of the olefin parallel to the metalkarbon bond.…”

Section: Discussionmentioning

confidence: 99%

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Dihydrofurans from α-diazoketones due to facile ring opening – cyclization of donor–acceptor cyclopropane intermediates

Lund¹,

Kennedy²,

Fallis³

1996

Can. J. Chem.

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A series of a-diazoketones, 8, 25,28,31, and 34, have been synthesized and their reaction with ethyl vinyl ether examined under various reaction conditions. In the presence of metal salts (Rh,(OAc),, Pd(OAc),, CuC1) the ethoxydihydrofurans 12,37,39,41, and 43 are produced. Sensitized irradiation of the a-diazoketone 8 afforded the dihydrofuran 12 plus cyclobutanone 7, while direct photolysis of a-diazoketones 8,25,28,31, and 34 gave the cyclobutanones 7,38,40,42, and 44, respectively. A sample of the cyclopropylketone 45 was isolated from the rhodium(I1) acetate mediated reaction of 34 and its facile rearrangement to dihydrofuran 43 demonstrated. Collectively, these results indicate that the initial product from the reaction of an a-diazoketone with an electron-rich alkene such as ethyl vinyl ether is a cyclopropylketone. The donnor-acceptor substitution pattern of this intermediate results in spontaneous rearrangement to a dihydrofuran. Thus a direct dipolar cycloaddition mechanism is not involved when a-diazoketones react with en01 ethers under metal-mediated conditions. Instead, these reactions follow a cyclopropanation rearrangement or, more accurately, cyclopropanation -ring opening -cyclization pathway.Key words: diazoketone, rhodium acetate, dihydrofuran, cyclopropylketone, vinyl ether.RCsumC : On a synthttist une strie d'a-diazocttones 8,25,28,31 et 34 et on a ttudit, dans difftrentes conditions, leur rtaction avec l'tther tthylvinylique. En prtsence de sels mttalliques (RH,(OAc),, Pd(OAC),, CuC1) on obtient les tthoxydihydrofurannes 12,37,39,41 et 43. L'irradiation sensibiliste de l'a-diazocttones 8 produit le dihydrofuranne 12 et la cyclobutanone 7, tandis que la photolyse directe des a-diazocttones 8,25,28,31 et 34 donne les cyclobutanones 7,38,40,42 et 44 respectivement. On a isolt un tchantillon de cyclopropylcttone 45 de la rtaction du compost 34 en prtsence de l'acttate de rhodium et on dtmontre sa transposition facile en dihydrofuranne 43. Collectivement, ces rtsultats indiquent que le produit initial de la rtaction d'une a-diazocttone avec un alcbne riche en tlectrons tel l'tther Cthylvinylique est une cyclopropylcttone. Le modble de substitution donneur-accepteur de cet intermtdiaire provient d'une transposition spontante en dihydrofuranne. Ainsi un mCcanisme de cycloaddition dipolaire directe n'est pas impliqut lorsque une a-diazocttone rtagit avec des tthers tnoliques en prtsence d'un mCtal. Au lieu de cela ces rtactions suivent une transposition cyclopropanique ou plus prtcistment un processus de cyclopropanation, d'ouverture du cycle du cyclopropane et de cyclisation.Mots cle's : diazocttone, acttate de rhodium, dihydrofuranne, cyclopropylcCtone, tther vinylique.[Traduit par la rtdaction]

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Dihydrofurans from α-diazoketones due to facile ring opening – cyclization of donor–acceptor cyclopropane intermediates

Lund¹,

Kennedy²,

Fallis³

1996

Can. J. Chem.

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“…Because the above catalysts generate electrophilic carbenoid species, and as cyclopropanation occurs, as a rule, at electronically enriched double bonds, [8,18] it is believed that electron density in fluorodiene 2 is noticeably displaced from the methylsubstituted double bond to the fluorovinyl unit.…”

Section: C] Ethyl Cis-and Trans-1-methyl-2-vinylcyclopropanecarboxylatementioning

confidence: 99%

Catalytic Cyclopropanation of Fluorine‐Containing Alkenes and Dienes with Diazomethane and Methyl Diazoacetate

et al. 2004

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The reactivities of various double bonds in fluorine-containing unsaturated compounds toward cyclopropanation with diazomethane and methyl diazoacetate with catalysis by copper, rhodium and palladium compounds were studied. In general, the presence of fluorine atoms attached to the double bond or arranged at neighbouring positions exerted a suppressive effect on the cyclopropanation of this bond. As would be expected, diazomethane in the presence of palla-

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Chromium Complex Catalyzed Synthesis of Spirocyclopropanes from Diaryl Diazo Compounds – Direct NMR-Spectroscopic Observation of a Carbene Complex Intermediate

Pfeiffer

Nieger

Dötz³

1998

Eur. J. Org. Chem.

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Stereoselectivity of catalytic cyclopropanation reactions. Catalyst dependence in reactions of ethyl diazoacetate with alkenes

Cited by 129 publications

References 2 publications

Dihydrofurans from α-diazoketones due to facile ring opening – cyclization of donor–acceptor cyclopropane intermediates

Dihydrofurans from α-diazoketones due to facile ring opening – cyclization of donor–acceptor cyclopropane intermediates

Catalytic Cyclopropanation of Fluorine‐Containing Alkenes and Dienes with Diazomethane and Methyl Diazoacetate

Chromium Complex Catalyzed Synthesis of Spirocyclopropanes from Diaryl Diazo Compounds – Direct NMR-Spectroscopic Observation of a Carbene Complex Intermediate

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