6553-48-6Relevant articles and documents
Evidence for pericyclic and stepwise processes in the cyclodimerization of chloroprene and 1,3-butadiene from pressure dependence and stereochemistry. Experimental and theoretical volumes of activation and reaction
Kl?rner, Frank-Gerrit,Krawczyk, Bernd,Ruster, Volker,Deiters, Ulrich K.
, p. 7646 - 7657 (2007/10/02)
From the pressure dependence of cyclodimerization of chloroprene, it has been concluded that volumes of activation may be useful for the distinction between competing concerted and stepwise cycloadditions. Accordingly, one of the [4 + 2] cyclodimers, 1,4-
Small Rings. Part 32. The Gas Phase Kinetics, Mechanism, and Energy Hypersurface for the Thermolyses of syn- and anti-Tricyclo2,5>-octane
Walsh, Robin,Martin, Hans-Dieter,Kunze, Michael,Oftring, Alfred,Beckhaus, Hans-Dieter
, p. 1076 - 1083 (2007/10/02)
The title reactions have been studied at low pressure (1-10 Torr) and in the temperature ranges 390-419 2,5/octane(syn-TCO)> and 412-445 K (anti-TCO).The major products from both compounds were cis,cis and cis,trans-cyclo-o
The C8H12-Energy Hypersurface Thermolysis of syn- and anti-Tricyclo2,5>octane. Experimental and Theoretical Studies
Martin, Hans-Dieter,Eisenmann, Erwin,Kunze, Michael,Bonacic-Koutecky, Vlasta
, p. 1153 - 1179 (2007/10/02)
The thermal behaviour of syn- and anti-tricyclo2,5>octanes 9 and 10 in the gas phase as well as in solution is investigated.Two main products are formed in parallel reactions: cis,cis-1,5-cyclooctadiene (11) and cis,trans-1,5-cyclooctadiene (15), the latter being partly isomerized to 11 under the reaction conditions.Minor products are cis-1,2-divinylcyclobutane (6), trans-1,2-divinylcyclobutane (16) and 4-vinyl-1-cyclohexene (17).Thermolysis of cis-1,2-divinylcyclobutane leads to small amounts of cis,trans-cyclooctadiene, presumably via a four-centre transition state.The tricyclics most likely prefer a stepwise isomerization.The decisive product-controlling factor seems to be the conformational mobility of intermediate diradicals.By comparison with the boat-Cope reaction of divinylcyclobutane the pericyclic six-centre transition state of this rearrangements is shown to lie energetically about 19 kcal/mol below the transition states in the thermolysis of 9 and 10.The azo compound 12 on heating fragments predominantly in a concerted manner in contrast to the photolysis.Theoretical methods are applied to unveil structure and bonding in the supposed intermediate diradicals.