- REACTIONS OF DIAZOALKANES WITH UNSATURATED COMPOUNDS. 6. CATALYTIC CYCLOPROPANATION OF UNSATURATED HYDROCARBONS AND THEIR DERIVATIVES WITH DIAZOMETHANE
-
A systematic study has been conducted of the catalytic reaction of diazomethane with cyclic and polycyclic unsaturated hydrocarbons, conjugated dienes, as well as with a series of functionalized unsaturated conpounds.The feasibility of using transition metal, nontransition metal, and rare earth metal compounds of, for example, Co, Ni, Zr, Rh, and Dy, has been demonstrated for the first time.It has also been established that Pd(acac)2 has very high activity as a catalyst for the cyclopropanation of terminal and endocyclic double bonds by diazomethane, and that its activity is reduced upon the introduction of n-donor ligands or in the presence of strong polar solvents.
- Dzhemilev, U. M.,Dokichev, V. A.,Sultanov, S. Z.,Khusnutdinov, R. I.,Tomilov, Yu. V.,et al.
-
p. 1707 - 1714
(2007/10/02)
-
- REACTION OF CYCLIC OLEFINS CONTAINING CYCLOPROPANE FRAGMENTS WITH DIAZOMETHANE IN THE PRESENCE OF PALLADIUM(II) ACETATE
-
The reaction of a series of cyclic olefins containing three-membered rings with diazomethane in the presence of palladium(II) acetate leads to the formation of high yields of the sterically least hindered cyclopropane derivatives.
- Lukin, K. A.,Zefirov, N. S.
-
p. 1487 - 1490
(2007/10/02)
-
- Nonhomogeneous Phase Effect on the Generation of Carbene Radical Anions in the Birch-Type Reduction of Bis(gem-dihalocyclopropyl) Compounds
-
The reduction of 1,2-bis(gem-dichlorocyclopropyl)ethane (5) with sodium metal (4 molar equiv with respect to 5) in a mixed solution of NH3-THF-EtOH, which separated a metallic liquid phase on mixing, gave the parent hydrocarbon product predominantly.On the other hand, analogous reduction of 5 with lithium metal, which produced a homogeneous colored solution, predominantly gave the di- and trichloro intermediate products.The unusual results of the reduction with a nonhomogeneous reductant mixture are explained in terms of a rapid and consecutive electron transfer tothe molecule which is taken into or located in the vicinity of the reductant phase. 3,3,8,8-Tetrachlorotricyclo2,4>octane behaved analogously.
- Oku, Akira,Yoshiura, Naoto,Okuda, Tomohisa
-
p. 617 - 619
(2007/10/02)
-
- Diademane and Structurally Related Compounds, I. Preparation and Characteristic Reactions of Some Tris-?-homobenzene Hydrocarbons
-
Diademane (5) and 1,6-Homodiademane (6) are the first hydrocarbons with cis-tris-?-homobenzene skeletons.They were prepared by photoisomerization of the olefinic precursors 8 (snoutene) and 15 (4,5-homosnoutene), respectively.In an analogous reaction the bridged trans-tris-?-homobenzene 7 was formed from 17 (endo,exo-bishomobarrelene). 7 is more easily obtained from 17 by rhodium(I)-catalyzed isomerization or from exo,exo-bishomobarrelene 18 by thermal rearrangement.The unbridged 4 was prepared using a newly developed synthetic sequence starting from 1,3-cyclohexadiene.The thermal rearrangement of 5 and 6 to triquinancene (9) and 1,10-homotriquinancene (16) is very facile; the gas phase kinetic parameters (ln k (5) = 33.7 - 31600/RT and ln k (6) = 32.2 - 28300/RT, both first order) strongly corroborate, that these rearrangements are concerted ?2S + ?2S + ?2S> cycloreversions. -labelled 4 upon thermolysis yields a trans-bicyclonona-3,7-diene (31 22) with a 12C-labelling pattern, which proves its formation via a 3-step mechanism.The first step in this sequence most probably is a ?2S + ?2S + ?2S> cycloreversion with ln k = 30.8 - 42000/RT (first order).Only the bridged compound 7 does not follow the sample path, probably due to excessive ring strain in the transition state, and prefers a stepwise cycloreversion leading to 18 and at least 5 secondary products.
- Kaufmann, Dieter,Fick, Hans-Heinrich,Schallner, Otto,Spielmann, Werner,Meyer, Lueder-Ulrich,et al.
-
p. 587 - 609
(2007/10/02)
-