Benzylidenecarbene as a probable intermediate in the interconversion of Ph¹³CCH and PhC¹³CH at 550 °C and 700 °C

Methods for the Chemical Synthesis of Fullerenes

“…Bond formation, however, requires not only that the requisite atoms approach each other but also that one atom be sufficiently reactive to "attack" the other and create the new bond. To fulfill this requirement, we exploited the "Roger Brown rearrangement" (Scheme 3), [27] a novel method for generating carbenes reversibly at high temperatures that was already well known to those of us who used FVP on a daily basis.…”

Thermal Rearrangement of Ethynylarenes to Cyclopentafused Polycyclic Aromatic Hydrocarbons: An Electronic Structure Study

“…The five possible mechanisms of the thermal rearrangement of ethynylarenes to CP-PAHs: (a) the unimolecular mechanism I, (b) the unimolecular mechanism II, (c) the free-radical mechanism III, (d) the free-radical mechanism IV, and (e) the free-radical mechanism V. the thermal scrambling of carbon atoms within the CtC moiety of ethynylbenzene20,21 does not conclusively establish the presence of high-temperature equilibria between ethynylarenes and 2-arylethylidenes. Similarly, the formation of benz[a]azulene(27) as a byproduct of the thermal cyclization of 2-ethynylbiphenyl(23) to phenanthrene(25) 21 can be explained equally well by the insertion of either the carbene(24) or the carbenelike radical (28)(Figure 3).…”

Methoden zur chemischen Synthese von Fullerenen

“…Diese Bindungsbildung setzt jedoch nicht nur voraus, dass sich die zu verknüpfenden Atome entsprechend nähern, sondern auch, dass ein Zentrum ausreichend reaktiv ist, um das andere "anzugreifen" und die neue Bindung zu schließen. Um diesen Erfordernissen zu entsprechen, nutzten wir die Roger-BrownUmlagerung (Schema 3), [27] eine neuartige Methode zur reversiblen Generierung von Carbenen bei höheren Temperaturen, mit der wir als routinierte FVP-Anwender bereits gut vertraut waren.…”