The photochemistry of ---phenylenediacrylate

Photoinduced Intermolecular [4+2] Cycloaddition Reaction for Construction of Benzobicyclo[2.2.2]octane Skeletons

“…We use 1b without 2 as starting material and we found that the compounds 8a and 8b were obtained in the total yield 51% under the standard conditions [Scheme , eq (8)], which were the products of intramolecular photoinduced [4+2] reaction, but the reaction time became longer because there was no dienophile 2 to trap the reactive intermediate cyclic-o-quinodimethane. This result is different from the Ploder’s work . Besides, we did not find the intramolecular reaction products [Scheme , eq (7)], and more importantly, out of all the experiments in Table we also did not find the intramolecular reaction products, and the time of this photoinduced intermolecular [4+2] reaction is less than the time of intramolecular reaction.…”

“…This result is different from the Ploder's work. 16 Besides, we did not find the intramolecular reaction products [Scheme 2, eq (7)], and more importantly, out of all the experiments in Table 2 we also did not find the intramolecular reaction products, and the time of this photoinduced intermolecular [4+2] reaction is less than the time of intramolecular reaction. This result revealed that the reaction rate of intermolecular reaction of 1b with 2a (k 1 ) is larger than the reaction rate of intramolecular reaction of 1b (k 2 ) [Scheme 2, eq (7), ( 8)] because there is dienophile (e.g., 2) which would trap the reactive intermediate cyclic oquinodimethane when the cyclic o-quinodimethane was once generated from the substrate 1 under UV light in the system.…”

Mechanistic insights into the thermal transformations of heterocyclic o-distyrylbenzenes: an experimental and computational study

“…1 Their preparation is relatively simple, 2 and with their extended delocalization of p electrons in the excited state they can induce new properties and the formation of new complex structures, difficult to prepare by the classical synthetic procedure. 3 In addition to well-known photochemical transformations of distyrylbenzenes, [4][5][6][7][8][9][10][11][12][13] over the past years, their thermal transformations in neutral and acidic [14][15][16][17][18][19] were also studied. 20 While thermal reaction in neutral medium did not indicate significant reactivity, acidic conditions can cause protonation of the double bond and the formation of new intramolecular products.…”