The three cycle mechanism of BBr3 facilitated demethylation of anisole reported by Kosak et al. was further investigated in terms of its application to BCl3 facilitated ether cleavage. Based on Lewis acidity trends of boron trihalides, BCl3 is a weaker Lewis acid than BBr3. Therefore, it may be observed that BCl3 does not proceed through the three cycle mechanism as efficiently as BBr3. Reactions performed by Kosak eat al. were reproduced with BCl3 as the demethylating agent along with several other reactions with modified conditions. Significant evaporation of the reactions occurred and this phenomenon caused the amount of conversion from anisole to phenol, observed via GC-FID analysis, to be very inconsistent. However, evidence of the cleavage of anisole by BCl3 has been observed. In order to obtain results consistent with the predictions for the three cycle mechanism, BCl3 should be purchased in a solvent that possesses a higher boiling point to prevent evaporation.
Conrad, Heidi, "Investigation of the Mechanism for BBr3 Facilitated Demethylation of Aryl-Methyl Ethers Applied to BCl3 Facilitated Ether Cleavage Based on Lewis Acidity Trends of Boron Trihalides" (2015). Honors Projects. 500.