Kinetic or Thermodynamic Product? Case Studies on the Formation of Regioisomers of Tetraphenyladamantanes.

So, the optimization study gave two different acid concentration/reaction time optima for the two fully symmetrical alkylation products TBro/iTBro. Keywords: adamantane; alkylation; crystallization; Friedel-Crafts reactions; regioselectivity EN adamantane alkylation crystallization Friedel-Crafts reactions regioselectivity 2473 2482 10 07/31/23 20230817 NES 230817 Graph Introduction Adamantane is a highly symmetrical, rigid hydrocarbon that may be considered the smallest three-dimensional subunit of the diamond lattice. Here we report the formation and isolation of the regioisomer tetrakis(4-bromo-2-methoxyphenyl)adamantane (iTBro) as the main product of the Friedel-Crafts reaction under the control of a strong Brønsted acid, indicating that this is the true thermodynamic product of the Friedel-Crafts alkylation of TOA. For the heavy halogens, the I para i -halo TAAs are the predominant products of equilibria induced by treatment with the strong Brønsted acid triflic acid, whereas fluoroanisole gives predominantly the regioisomeric I ortho i -halogen product under conditions that allow for establishing isomerization equilibria. [Extracted from the article]