Methyltitanium Trichloride

[2747-38-8] CH3Cl3Ti (MW 169.27) InChI = 1S/CH3.3ClH.Ti/h1H3;3*1H;/q;;;;+3/p-3 InChIKey = DGXOWMLKUUUVMZ-UHFFFAOYSA-K (nonbasic nucleophilic reagent with high Lewis acidity;1, 2 adds to aldehydes, ketones, and acetals with high chemo- and stereoselectivity;1, 2 reagent for the SN1 substitution of tertiary halides3 and the geminal dimethylation of carbonyl compounds4, 5) Alternate Names: trichloromethyltitanium; methyltitanium(IV) trichloride. Physical Data: mp 29 °C; bp 37 °C/1 mmHg. Solubility: sol most commonly used aprotic solvents, including pentane, Et2O, THF, CH2Cl2. Forms octahedral complexes with bidentate ligands such as glycol ethers, ethylenediamines, and diphosphines as well as with solvents such as Et2O and THF. Form Supplied in: purple crystals; not available commercially. Analysis of Reagent Purity: 1H NMR: 2.9 ppm (s). Preparative Methods: MeTiCl3:6 ether-free reagent, suitable for chelation-controlled carbonyl additions and SN1 substitutions, can be prepared from a 2∶1 mixture of Titanium(IV) Chloride and Me2Zn5 in CH2Cl2 at −78 °C. The resulting solution can be used as is or distilled under vacuum. A 1∶1 mixture of TiCl4 and Me2Zn produces Dichlorodimethyltitanium, which is more effective for SN1 substitutions.5 MeLi–TiCl4–Et2O:2 solutions of MeTiCl3 in Et2O can be more conveniently prepared from Methyllithium and TiCl4. Other organometallics, such as Methylmagnesium Bromide, can also be used. In the workup, simple quenching with ice water is preferred. The use of Sodium Carbonate may lead to cumbersome emulsions of TiO2, which can be avoided with NH4F or Potassium Fluoride. Handling, Storage, and Precautions: moisture sensitive; stable at low temperature in the dark. At rt, it decomposes over several hours. Me2Zn is very pyrophoric in a pure form.