A Stereochemical and Kinetic Study of the Conversion of Methyl Cyclopropyl Ketones to 4,5-Dihydrofurans
15 May 1973-Canadian Journal of Chemistry (NRC Research Press Ottawa, Canada)-Vol. 51, Iss: 10, pp 1487-1493
TL;DR: The thermal and photochemical conversion of (1R*,2R*,3S*), (1S*, 2R*, 3S*) and 1-acetyl-1,2-dimethyl-3-phenylcyclopropane (1, 2, and 3) to cis-and trans-2, 3, 4, 4-trimethyl-5, 5, 6, 7, 8-d...
Abstract: The thermal and photochemical conversion of (1R*,2R*,3S*), (1S*,2R*,3S*), and (1S*,2R*,3R*)-1-acetyl-1,2-dimethyl-3-phenylcyclopropane (1, 2, and 3) to cis- and trans-2,3,4-trimethyl-5-phenyl-4,5-d...
Citations
More filters
••
TL;DR: TBA[Fe] catalyzes the rearrangement of vinyl and arylcyclopropanes under thermal or photochemical conditions.
Abstract: The base metal complex Bu4N[Fe(CO)3(NO)] (TBA[Fe]) catalyzes the rearrangement of vinyl and arylcyclopropanes both under thermal or photochemical conditions to give the corresponding vinyl or aryldihydrofurans in good to excellent yields. Under photochemical conditions the reaction is performed at room temperature. Spectroscopic investigations show that the metal carbonyl catalyst is not decarbonylated. The best performance was observed at a wavelength of 415 nm. icMRCI+Q analysis of the excited singlet and triplet states of the [Fe(CO)3(NO)] anion was performed and used to calculate the vertical excitation energies which are in good agreement with the experimental data. CASSCF analysis indicates that the Fe center in all excited states of the ferrate becomes more electrophilic while adopting a distorted tetrahedral configuration. Both aspects have a positive synergistic effect on the formation of the initial π-complex with the incoming organic substrate.
47 citations
••
TL;DR: The rates of the Cope rearrangement of 2,5-dicyano-3-methyl-hexa-1, 5-diene (12), (E)- and (Z)-2.5-dimethoxy-carbonyl-3 -methyl-hexa-hepta-1.5 -diene ((E- and Z)-15) were measured in decane solution in the temperature range of 50 to 150° as discussed by the authors.
Abstract: On the Mechanism of the Cope Rearrangement
The rates of the Cope rearrangement of 2,5-dicyano-3-methyl-hexa-1, 5-diene (12), (E)- and (Z)-2, 5-dicyano-hepta-1,5-diene ((E)- and (Z)-14) as well as of 2, 5-dimethoxycarbonyl-3-methyl-hexa-1,5-diene (13) and (E)- and (Z)-2,5-dimethoxycarbonyl-hepta-1,5-diene ((E)- and (Z)-15) were measured in decane solution in the temperature range of 50 to 150° (see Tables 5 and 8 to 12). A detailed English summary of this work is given in [1 b].
40 citations
••
TL;DR: The reaction of secondary nitro alkanes with α,β-unsaturated ketones has been shown to yield 4,5-dihydrofurans and furans as discussed by the authors.
25 citations
••
TL;DR: In this paper, a general method for the preparation of α-phenylselanyl enones is described, and a 1,4-addition is used to obtain cyclopropanes and/or dihydrofurans.
23 citations
••
TL;DR: A cyclic β-dicarbonyl phenyliodonium ylide reacted with various substituted styrenes under Rh2(OAc)4 catalysis to give cyclopropanes and dihydrofurans in a highly regioselective fashion.
Abstract: A cyclic β-dicarbonyl phenyliodonium ylide reacted with various substituted styrenes under Rh2(OAc)4 catalysis to give cyclopropanes and dihydrofurans in a highly regioselective fashion. When styrenes with electron-donating substituents or disubstituted were employed, only dihydrofurans were isolated instead. A mechanism involving two competing pathways rationalizes the results.
22 citations