Electrophilic Substitution of Anionic Aluminabenzene via Sequential Reactions with Electrophile and Base

Abstract

The reaction of an isolable anionic aluminabenzene with electrophiles, such as MeOTf and Me 3 SiOTf, was investigated. The nucleophilic attack on the pentadienyl moiety of the aluminabenzene ring proceeded at the 4position to form the aluminacyclohexadiene bearing a Me or Me 3 Si group. Treatment of the resulting methyl-or silylsubstituted aluminacyclohexadiene with the bulky base MesLi gave the rearomatized anionic aluminabenzene bearing a Me or Me 3 Si group. Thus, this sequential reaction would be considered as an electrophilic substitution of aluminabenzene. The substituent effect of Me and Me 3 Si groups on the aluminabenzene ring was also estimated on the basis of experimental and theoretical studies.

Heavier element-containing aromatics of [4n+2]-electron systems

“…Aluminabenzene 6CAl1 undergoes electrophilic substitution in a stepwise manner (Scheme 4-1 B). 186 The reactions of 6CAl1 with MeOTf or TMSOTf gave the corresponding aluminacyclohexadienes 6CAl1-Me or 6CAl1-TMS. Subsequent treatment with MesLi gave the rearomatized anionic aluminabenzenes as yellow (6CAl4) or colorless (6CAl5) crystals, respectively.…”

Aluminabenzene‐based Lewis superacids and weakly coordinating anions

“…Taking into account that only borabenzene‐based Lewis unsaturated acids are well described in the literature, there seem to be plenty compounds based on remaining elements of the 13th group whose structures and properties are yet to be investigated. Nevertheless, the increasing number of publications on this type of compounds appearing in recent years indicates the growing interest in scientific community 14–17 …”

“…Nevertheless, the increasing number of publications on this type of compounds appearing in recent years indicates the growing interest in scientific community. [14][15][16][17] Lewis acids themselves have a wide spectrum of applications in organic synthesis. Perhaps the most prominent example include the use of AlCl 3 as a catalyst for Friedel-Crafts reactions and utilizing ZnCl 2 or BF 3 in the Diels-Alder reaction.…”