- Interaction of diazoalkanes with unsaturated compounds. 12. Stereochemistry of cyclopropanation of norbornenes with diazomethane in the presence of transition metal complexes
-
The stereochemistry of cyclopropanation of norbornenes with diazomethane in the presence of Cu, Pd, and Rh compounds has been studied.Stereoselectivity of the cyclopropanation depends on the nature of the transition metal and does not depend on its valent state or ligand environment.The reaction proceeds predominantly as exo-cycloaddition of the methylene fragment.The greatest amount of endo-isomer (up to 47 percent) is formed in cyclopropanation of norbornadiene and exo-tricyclo2,4>oct-6-ene in the presence of Cu and Rh compounds.
- Dzhemilev, U. M.,Dokichev, V. A.,Maidanova, I. O.,Nefedov, O. M.,Tomilov, Yu. V.
-
p. 697 - 700
(2007/10/02)
-
- 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)
-
- TRANSFORMATIONS OF CYCLOPROPANE IN RIGID HYDROCARBON SYSTEMS USING PLATINUM(II)
-
Using the cyclopropane adducts of the norbornyl system, platinacyclobutane complexes were prepared.In this article, the reactions of these platinum(IV) complexes with heat, CH2N2 and DMSO are discussed.In each case, a unique olefinic product has been produced.In another reaction, the platinacyclobutane of phenylcyclopropane is treated with CH2N2 to produce styrene.
- Jennings, P. W.,Ekeland, R. E.,Waddington, M. D.,Hanks, T. W.
-
p. 429 - 436
(2007/10/02)
-
- UNUSUAL CYCLOADDITIONS OF 4-PHENYL-1,2,4-TRIAZOLIN-3,5-DIONE TO ENDO- AND EXO-TRICYCLO2,4>OCT-6-ENES
-
4-phenyl-1,2,4-triazolin-3,5-dione readily cycloadds to endo- and exo-tricyclo2,4>oct-6-enes to give Δ1-1,2-diazetines besides skeletally rearranged products.All adducts can be converted to the respective azo compounds which exhibit some unusual thermal and photochemical behavior.
- Erden, Ihsan
-
p. 263 - 266
(2007/10/02)
-
- Reactions of Cyclopropyl Chlorides with Metals and Lithium Naphthalene Radical Anion and Dianion
-
The reaction of exo- and endo-anti-3-chlorotricyclo2,4>oct-6-ene with magnesium in THF followed by deuterolysis gave syn/anti deuteration ratios of 2.2 and 0.42, respectively, with 85percent monodeuterium incorporation.Analysis of the exo hydrocarbon involved epoxidation followed by a shift-reagent study with Eu(fod)3.Reaction of the same halides with Na/t-BuOD gave 95percent deuterium incorporation with syn/anti ratios of 1.2 and 0.37, respectively.Similarly, reaction of anti-3-chloro-exo-tricyclo2,4>octane with Na, K, and Li in t-BuOD/THF gave 95percent deuterium incorporation with syn/anti ratios of 2.11, 1.25, and 1.70.No effect of temperature or solvent composition was observed in the potassium reduction.Reaction of this halide with Li in Et2O followed by D2O gave 87percent deuterium incorporation with a syn/anti ratio of 2.1, while reaction with lithium naphthalene in THF at -78 deg C followed by addition of D2O gave 96percent deuterium incorporation with a syn/anti ratio > 100.All of the above results are described in terms of radical equilibria and competing electron transfers.Reaction of anti-3-bromo-exo-tricyclo2,4>octane with butyllithium in ether at 0 deg C followed by deuterolysis gave entirely anti deuteration (anti/syn ratio > 16) with 95percent deuterium incorporation.Reaction of anti-3-chloro-exo-tricyclo2,4>octane with lithium naphthalene dianion proceeded at -78 deg C in THF with a rate constant of 5.5 x 10-2 M-1 min -1, while under identical conditions lithium naphthalene exhibited a rate constant of 1.0 M-1 min-1.Deuterolysis of the dianion solution gave a syn to anti deuterium incorporation ratio greater than 50.
- Freeman, Peter K.,Hutchinson, Larry L.
-
p. 3191 - 3198
(2007/10/02)
-