30889-20-4Relevant articles and documents
Transition Metal-Diene Complexes. Part 4. The Crystal and Molecular Structure and Isomerization of η-Cyclopentadienyl(η-3-methoxycarbonyl-cyclohexa-1,4-diene)rhodium(I)
Drew, Michael G. B.,Regan, Catrionia M.,Nelson, S. Martin
, p. 1034 - 1040 (1981)
Crystals of the title compound, , are monoclinic, space group I2/a with cell dimensions a=28.124(14), b=6.141(8), c=14.569(11) Angstroem, β=112.43(9) deg, and Z=8.The intensities of 1 325 reflections above background were collected by counter methods and refined to R 0.052.The rhodium atom is bonded to the five carbon atoms of the planar cyclopentadienyl ring and to the four olefinic carbon atoms of the cyclohexa-1,4-diene.The cyclohexa-1,4-diene ring is in the boat conformation with the two saturated carbon atoms lying 0.66, 0.70 Angstroem above the plane of the four olefinic carbons in a direction away from the metal.The carbomethoxy-subtituent is planar and occupies an axial position with respect to the cyclohexadiene boat.The title complex undergoes a kinetically controlled isomerization when heated in toluene or acid-free o-dichlorobenzene to a mixture of complexes containing co-ordinated 5-methoxy-carbonyl- (major product) and 2-methoxycarbonyl-cyclohexa-1,3-diene (minor product).In the presence of acid in o-dichlorobenzene the major product undergoes a secondary isomerization to the complex containing co-ordinated 1-methoxycarbonylcyclohexa-1,3-diene.For the primary isomerization a mechanism involving the formation of a hydro-η3-allylic intermediate is proposed in which the rate-determining step is a carbon-to-metal hydride-ion transfer.For the secondary isomerization, in the presence of acid, a reverse metal-to-carbon hydrogen transfer is believed to operate.
Enantioselective divergent approaches to both (-)-platensimycin and (-)-platencin
Hirai, Sho,Nakada, Masahisa
experimental part, p. 518 - 530 (2011/03/19)
Enantioselective divergent approaches to (-)-platencin and (-)-platensimycin have been developed. A rationally designed chiral synthetic intermediate, possessing a useful α,β-unsaturated sulfone functionality, which served as a masked ketone as well as a good Michael acceptor, was successfully prepared via the highly enantioselective catalytic asymmetric intramolecular cyclopropanation (CAIMCP) developed in our laboratory. Copyright
Asymmetric synthesis by the intramolecular haloetherification reaction of ene acetal: Discrimination of prochiral dienes in cyclohexane systems
Fujioka, Hiromichi,Kotoku, Naoyuki,Sawama, Yoshinari,Kitagawa, Hidetoshi,Ohba, Yusuke,Wang, Tsung-Lung,Nagatomi, Yasushi,Kita, Yasuyuki
, p. 952 - 957 (2007/10/03)
A novel asymmetric synthesis of the cyclohexane derivative functionalized by some substituents has been developed from the diene acetals (1), prepared from the corresponding diene aldehyde and (+)-hydrobenzoin. The treatment of 1 with NBS in the presence
