Reactions of Hydroxymesitylboranes with Metal Alkyls: An Approach to New Sterically Hindered (Metaloxy)mesitylboranes

Reactions of mesitylboronic acid with alkyl derivatives of aluminum R3Al (R = Me, Et, Bui), gallium (Me3Ga), and zinc (Et2Zn) were investigated. The treatment of mesitylboronic acid, MesB(OH)2, with trimethylgallium afforded the discrete dimer [μ-(MesB(OH)O)GaMe2]2 (1), which is the simple example of a O-metalated boronic acid with no hydrogen bonding in the crystal lattice. In addition, the reaction of dimesitylborinic acid, Mes2BOH, with diethylzinc produced the low-valent zinc compound [(μ-Mes2BO)ZnEt]2 (2), which was also characterized by X-ray diffraction.