78811-56-0Relevant academic research and scientific papers
1,2-Photoadditions of Stilbenes and Diarylacetylenes to Bicyclic 1,4-Cyclohexadienes: Propellanes and Substitutive 1,2-Adducts
Kaupp, Gerd,Stark, Michael
, p. 2217 - 2237 (2007/10/02)
The photoreactions of stilbene, 4,4'-dichloro-, 4,4'-dicyano-, 4,4'-dimethoxystilbene, diphenylacetylene, and bis(4-cyanophenyl)acetylene with 2,3,4,7-tetrahydroindene and 1,4,5,8-tetrahydronaphthalene have been investigated.Despite severe steric hindrance and because of electrostatic support the propellanes 3, 12, 23, 26 are formed as the major -cycloadducts.The products of dehydrogenation 41, 44, 45 and hydrogenation 29 are obtained from them.Further major products of the photolyses are the substitutive 1,2-adducts 4, 5, 14, 15, 24, 27, whereas the ene-adduct s 25, 28 occur only in trace amounts.The mechanistic grounds are discussed in terms of diradicals with consideration of exciplex emissions and with the aid of comparative reactions involving 1,4-cyclohexadiene and methyl cinnamate.The protolyses of several propellanes with varing degrees of hydrogenation are described (decomposition, dehydrocyclization, intramolecular cycloaddition and 1,5-shift).The structures of the products have been determined spectroscopically (IR, UV, fluorescence, 1H-NMR, 13C-NMR) and in part by chemical degradation and independent synthesis.
