A method of synthesis of .beta.-methylfurans and .alpha.-methylene and .beta.-methylene .gamma.-lactones. Two menthofuran syntheses

Wenkert, Ernest; Alonso, Miguel E.; Buckwalter, Brian L.; Chou, Kechia J.

doi:10.1021/ja00456a040

Cited by 130 publications

(20 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Em algumas reações não é possível isolar-se o ciclopropano intermediário obtendo-se diretamente o diidrofurano 3q,r . No Esquema 22 estão apresentados vários diidrofuranos 83 49 , 85 50 , 87 51 , 89 52 , 91 53 e 93 54 obtidos a partir de reações com enóis éteres cíclicos e os diidrofuranos 95 52 , …”

Section: Aplicações De Compostos Diazo Carbonílicos Nas Sínteses De Dunclassified

See 1 more Smart Citation

Compostos alfa-diazo carbonílicos: uma estratégia atraente para a síntese orgânica

Ferreira¹,

Pereira²,

Souza³

et al. 2001

Quím. Nova

View full text Add to dashboard Cite

Section: Aplicações De Compostos Diazo Carbonílicos Nas Sínteses De Dunclassified

“…Por exemplo, o terpeno mentofurano 107 (Esquema 23) foi obtido a partir do intermediário diidrofurânico 106 53,59 . Os furanos também podem ser preparados diretamente a partir da inserção de composto diazo carbonílico em alquinos 60-62 , como indicado a seguir para o furano 108 51 .…”

Section: Esquema 22 Diidrofuranos Preparados a Partir De Enóis éTereunclassified

Compostos alfa-diazo carbonílicos: uma estratégia atraente para a síntese orgânica

Ferreira¹,

Pereira²,

Souza³

et al. 2001

Quím. Nova

View full text Add to dashboard Cite

“…The ease with which the initial cyclopropane undergoes a 1,3-sigmatropic shift is therefore both substituent and substrate dependent (4). For example, the spirosystem 14 may be isolated, but the related cyclopropane 1 5 was not detected when dimethyl diazomalonatereacted in the presence of copper with 1-methoxycyclohexene (5). Other methoxy cyclopropanes also rearranged more readily than the corresponding ethoxy-substituted derivatives (6).…”

Section: Introductionmentioning

confidence: 99%

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

Lund¹,

Kennedy²,

Fallis³

1996

Can. J. Chem.

View full text Add to dashboard Cite

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]

show abstract

“…In fact, exceptions to this rule are rare. 7 This is understandable, given the presence of the additional acceptor group. France and coworkers initially reported the formation of alkoxy-substituted cyclopropane dicarbonyls from reactions of β-heteroarylketo-α-diazoesters with alkoxy alkenes, 8 but later reassigned the correct structures to be dihydrofurans.…”

mentioning

confidence: 99%

Acetoxy-Substituted Cyclopropane Dicarbonyls as Stable Donor–Acceptor–Acceptor Cyclopropanes

Reyes

Mead

2015

Synthesis

View full text Add to dashboard Cite

show abstract

A method of synthesis of .beta.-methylfurans and .alpha.-methylene and .beta.-methylene .gamma.-lactones. Two menthofuran syntheses

Cited by 130 publications

References 0 publications

Compostos alfa-diazo carbonílicos: uma estratégia atraente para a síntese orgânica

Compostos alfa-diazo carbonílicos: uma estratégia atraente para a síntese orgânica

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

Acetoxy-Substituted Cyclopropane Dicarbonyls as Stable Donor–Acceptor–Acceptor Cyclopropanes

Contact Info

Product

Resources

About