Experimental verification of halomethyl carbinol synthesis from carbonyl compounds using a TiCl4–Mg bimetallic complex promoter

Abstract

A critical evaluation of the feasibility of a previously published method for synthesising halomethyl carbinols from carbonyl compounds and CH₂Br₂ or CH₂Cl₂ using a bimetallic TiCl₄–Mg complex is presented. The synthesis of compounds lacking the –CH₂– group in their structure was achieved by following the procedures proposed in the reference literature or by introducing modifications to selected process parameters. These compounds were not identified as expected β-halohydrins but as products of reductive dimerisation or subsequent pinacolic rearrangement of carbonyl substrates. This paper proposes a formation mechanism of vicinal 1,2-diols in the presence of a TiCl₄–Mg system, supported by experimental data and theoretical DFT calculations (DFT/B3LYP).