Preparation and Identification of Diphenylboron Cation in Solution

Abstract

Recently, we reported that the treatment of diphenylchloroborane with nucleophile such as pyridine in CD₂Cl₂ formed the 1:1 adduct, which gave the sp² cation in CD₃NO₂ by the addition of SbCl₅. On the other hand, the sp² cation in CD₃NO₂ is considered to be weakly coordinated with CD₃NO₂, which is indicated by its ¹¹B and ¹³C NMR specta. However, the structure of the sp² cation in CD₃NO₂ has not been confirmed yet. Accordingly, it is necessary to change leaving groups, nucleophiles, Lewis acids, and solvents in order to clarify the structure of the boron cation and to ascertain the condition of its formation. Furthermore, the structure of the boron cation in solution was estimated based on the optimized structure by ab initio calculation.