2175-91-9Relevant articles and documents
Reversible Diels-Alder reactions for the generation of dynamic combinatorial libraries
Boul, Peter J.,Reutenauer, Philippe,Lehn, Jean-Marie
, p. 15 - 18 (2007/10/03)
(Chemical Equation Presented) Condensation reactions between various dienes and dienophiles have been screened for reversibility. Functionalized fulvenes, bearing in particular biological groups, and cyanolefins have been found to react rapidly and reversibly, in the temperature range from -10 to +50°C. These results pave the way for the development of dynamic combinatorial libraries based on reversible Diels-Alder chemistry.
The effect of pressure on retro Diels-Alder reactions
Klaerner, Frank-Gerrit,Breitkopf, Volker
, p. 2757 - 2762 (2007/10/03)
The activation and reaction volumes (ΔV(≠)/ΔV) were determined for the retro Diels-Alder reactions of the parent dihydrobarrelene 1a, its 2- cyano derivative 1b, the exo and endo Diels-Alder adducts of maleic anhydride to naphthalene exo-, endo-4, and the exo and endo Dies-Alder adducts of N- phenylmaleic imide to 6,6-dimethylfulvene exo-, endo-8 from the pressure dependence of the rate constants and the partial molar volumes (V) of reactants and products at various temperatures. The cleavage of exo-4, endo- 4, and exo-8 are slightly accelerated by pressure showing negative volumes of activation (V(≠) 0). From the analysis of the volume data including the van der Waals volumes (V(w)) one can conclude that the packing coefficients of the pericyclic transition states are equal to or even larger than those of the corresponding Diels-Alder adducts. This finding may be explained with the restriction of the degrees of freedom in the transition states leading to a contraction of the expansion volume.
Carbene Reactions, XVIII. Thermal Behaviour of 7-Alkylidenebicycloheptadiene Derivatives
Hoffmann, Reinhard W.,Riemann, Achim,Mayer, Bernhard
, p. 2493 - 2513 (2007/10/02)
Thermolysis of 7-alkylidenenorbornadienes 2 results in a retro-Diels-Alder cleavage to fulvenes and acetylene.A different mode of cleavage - into benzene and a carbene - is observed with such derivatives of 2 which carry ?- or ?-donor functions at C-8.The dependence of the reaction pathways on the nature of the substituent at C-8 is discussed on the basis of MO-calculations.