1755-05-1Relevant articles and documents
Functionalization of saturated hydrocarbons. High temperature bromination of octahydropentalene. Part 19
Günba?, Duygu D.,Algi, Fatih,H?kelek, Tuncer,Watson, William H.,Balci, Metin
, p. 11177 - 11183 (2005)
The synthesis and thermal bromination of octahydropentalene was studied. The reaction afforded 1a,3a,4b,6b-tetrabromo-1,2,3,4,5,6-hexahydropentalene (14) with remarkable regio- and stereospecificity. The structure of the product was determined by 1H and 13C NMR data and single X-ray structural analysis. The treatment of octahydropentalene with tenfold bromine gave the octabromopentalene derivative. The formation mechanism of the products is discussed.
Evidence for Single Electron Transfer in the Reactions of Lithium Dimethylcuprate with Alkyl Halides
Ashby, E. C.,Coleman, David
, p. 4554 - 4565 (2007/10/02)
A variety of methods have been utilized to explore the occurence of radical intermediates and free-radical chain processes initiated by electron transfer in the reactions of lithium dimethylcuprate with alkyl halides.The effect of leaving group, nature of the cuprate species, and ratio of cuprate to substrate, solvent, hydrogen atom donor, and other additives on the rate of and product distribution were investigated by using a cyclooctenyl radical probe.The presence of significant amounts of radicals strongly supports single electron transfer (SET) as a major pathway for the reaction of secondary iodides with LiCuMe2.There is some evidence of single electron transfer also accurring with secondary bromides, but tosylates appear to be reacting entirely by a SN2-like pathway.The role of dicyclohexylphosphine (DCPH) as an additive in the reaction was investigated with the result that it was shown to be capable of behaving in a unique manner depending on wheter the substrate is an alkyl iodide or bromide.The product distribution, rate, and effect of p-dinitrobenzene on the reaction of 5-iodo-1-cyclooctene were compared with three other probes and the results demonstrate that at least three reaction pathways are involved to varying degrees.These pathways could involve the initiation of free radicals or radical anion (SRN1) chain processes. these studies also demonstrate how changes in the substrate can alter the predominant reaction pathways that are followed.
Photochemistry of Alkenes. 9. Medium-sized cycloalkenes
Kropp, Paul J.,Mason, J. Derek,Smith, Gardiner F. H.
, p. 1845 - 1849 (2007/10/02)
The behavior of three medium-sized cycloalkenes cyclooctene (10), cyclodecene (17) and cyclododecene (21) on direct irradiation in pentane and methanol solution has been studied.The results are summarized in Tables 1-3.Irradiation of medium-sized cycloalkenes is a convenient procedure for the preparation of bicyclic products (cf. 13, 14, 19, 20 and 23) through transannular insertion reactions of carbene intermediates (cf. 11, 18, and 22) thought to arise from rearrangement of the 1 state via a 1,2-hydrogen shift.The formation of trans-decalin (20) is in contrast to the reported formation of the cis isomer on base-initiated decomposition of the corresponding tosylhydrazone.None of the three cycloalkenes 10, 17, or 21 underwent competing nucleophilic trapping of the 1 state in methanol, in contrast with other alkenes previously studied.However, cyclododecene (21) afforded the methyl ether 25, which apparently resulted from protonation of the 1(?,?*) state, and the epoxide 26, which is thought to arise from electron transfer to oxygen by the 1 state followed by protonation of the resulting superoxide ion and oxidation of unreacted cyclododecene (21).
