Experimental verification of halomethyl carbinol synthesis from carbonyl compounds using a TiCl-Mg bimetallic complex promoter

A critical evaluation of the feasibility of a previously published method for synthesising halomethyl carbinols from carbonyl compounds and CH 2 Br 2 or CH 2 Cl 2 using a bimetallic TiCl 4 -Mg complex is presented. The synthesis of compounds lacking the -CH 2 - 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 TiCl 4 -Mg system, supported by experimental data and theoretical DFT calculations (DFT/B3LYP). A mechanism for the formation of vicinal 1,2-diols in the presence of a bimetallic TiCl 4 -Mg promoter is proposed, supported by the analysis of experimental data (twelve examples) and theoretical DFT calculations (DFT/B3LYP).