Participation of Non-Conjugated Double Bonds in Diels-Alder Reactions. A kinetic study of the addition of tropone to norbornens

A kinetic study of Diels-Alder additions between norbornene derivatives acting as dienophiles and the dienes tropone, perchlorocyclopentadiene and 9,10-dimethylanthracene is presented. The results suggest that tropone thereby acts as an electron acceptor, classifying these reactions then as Diels-Alder additions with ‘inverse electron demand’. The role of non-reacting double bonds was investigated using 7-alkylidenorbornene derivatives as dienophiles. These show comparable reactivity in ‘normal’ but enhanced reactivity in ‘inverse electron demand’ Diels-Alder additions. This outcome is interpreted in terms of frontier orbital interactions between the reactants using photoelectron spectroscopical results as a basis for the qualitative perturbation treatment. It is suggested that the enhanced reactivity in the case of the 7-alkylidene derivatives does not necessitate the consideration of a direct (‘through-space’) participation of the non-reacting double bond.

[1]  R. F. Hudson.  Störungstheoretische Behandlung der Chemischen Reaktivität , 1973 .

[2]  W. C. Herndon.  Theory of cycloaddition reactions , 1972 .

[3]  Michael J. S. Dewar,et al.  Aromaticity and Pericyclic Reactions , 1971 .

[4]  Roald Hoffmann,et al.  Interaction of orbitals through space and through bonds , 1971 .

[5]  K. Houk,et al.  Novel double [6 + 4] cycloaddition of tropone to dimethylfulvene , 1970 .

[6]  A. Harget,et al.  Ground states of .sigma.-bonded molecules. X. Extension of the MINDO/2[modified intermediate negelect of differential overlap/2] method to compounds containing nitrogen and/or oxygen , 1970 .

[7]  M. Dewar,et al.  Ground states of .sigma.-bonded molecules. IX. MINDO [modified intermediate neglect of differential overlap]/2 method , 1970 .

[8]  R. F. Sprecher,et al.  tert-Butyl-substituted cyclopentadienones , 1969 .

[9]  Roald Hoffmann,et al.  Conservation of orbital symmetry , 1968 .

[10]  Y. Fujise,et al.  Reaction of Tropone with Cyclopentadiene , 1966 .

[11]  Kenichi Fukui,et al.  An MO-Theoretical Illumination for the Principle of Stereoselection , 1966 .

[12]  C. Jutz,et al.  Über die cycloaddition von diphenylketen an tropon , 1966 .

[13]  J. Sauer,et al.  Diels‐Alder‐Additionen mit „inversem”︁ Elektronenbedarf , 1962 .

[14]  T. Nozoe,et al.  Tropones. V. Addition Reaction of Tropone and Maleic Anhydride , 1960 .

[15]  T. Koopmans,et al.  Über die Zuordnung von Wellenfunktionen und Eigenwerten zu den Einzelnen Elektronen Eines Atoms , 1934 .