13920-54-2Relevant articles and documents
On the cis-Glycol and the Epoxide of Benzvalene
Christl, Manfred,Leininger, Hartmut,Kemmer, Petra
, p. 2963 - 2987 (2007/10/02)
By means of standard methods, benzvalene (1) can be transformed into the cis-glycol 2, from which derivatives such as the ditosylate 3, the cyclic carbonate 4, and the cyclic orthoacetates 5 and 6 are readily prepared.Irradiation causes thiophenol to add across the central bond of the bicyclobutane moiety of 2 with formation of the thioether 8.The solvolysis of 3 in aqueous acetone leads to endo,endo-tricyclo2,6>hexane-3,5-diol (11). - The epoxide 18 of benzvalene (1) may be synthesized starting either from the orthoesters 6 via the trans-chlorohydrin acetate 17 or directly from 1 with N-benzoylpercarbamidic acid, the latter reaction being the better one.Initially, the thermolysis of 18 produces 2-oxabicyclohepta-3,6-diene (19) which in part isomerizes to oxepin (20)/benzene oxide (21).In the thermal decomposition of 3,4-dideuterated 18, the labels end up in positions 5 and 6 of 19.If 18 is thermolyzed in high concentration 19, and 21 undergo Diels-Alder addition to a considerable extent to form the pentacyclic product 22.Epoxide 18 adds acetic acid and, under irradiation, thiophenol resulting in 1:1 adducts of the tricyclo2,6>hexane type (29 and 28, respectively).On slight warming, the diol monoacetate 29 rearranges to the corresponding bicyclohex-2-ene derivative 30, which is converted into its bicyclohex-2-ene isomer 31 at 130 deg C.Depending on the solvent and the temperature, LiAlH4 reduces 18 either to almost pure tricyclo2,6>hexan-3-ol (32) or to a 1:1 mixture of 32 and endo-tricyclo2,6>hexan-3-ol (33).On the basis of the NMR data of the corresponding methyl ethers 34 and 35, a structure assignment in the literature has to be revised.
