Titanium(III) Chloride–Potassium

(TiCl3) [7705-07-9] Cl3Ti (MW 154.23) InChI = 1S/3ClH.Ti/h3*1H;/q;;;+3/p-3 InChIKey = YONPGGFAJWQGJC-UHFFFAOYSA-K (K) [7440-09-7] K (MW 39.10) InChI = 1S/K InChIKey = ZLMJMSJWJFRBEC-UHFFFAOYSA-N (combination of reagents used for the in situ generation of highly oxophilic low-valent titanium species2 which are used to effect the reductive coupling of carbonyl groups2 (McMurry coupling) and reductive deoxygenations3) Physical Data: see Titanium(III) Chloride and Potassium. Solubility: TiCl3: sol alcohol, hydrochloric acid; v. slightly sol DME, THF. K: insol DME, THF. Form Supplied in: TiCl3: violet, air-sensitive solid. K: metal under paraffin. Preparative Methods: potassium metal (3.2 equiv) is washed with hexane and added to a slurry of titanium(III) chloride (1 equiv) in THF at rt under an inert atmosphere. The mixture is heated under reflux for 1 h, during which time the reaction mixture turns black. The mixture is cooled to rt and is then ready for the addition of the reaction substrates. Handling, Storage, and Precautions: care is required when handling potassium because it reacts violently with water and protic solvents, liberating highly flammable gases which are readily ignited. Titanium(III) chloride should be stored and used under argon, preferably in a glove bag or box. The low-valent titanium reagent is sensitive to air and moisture; therefore to obtain good yields, it must be freshly prepared. All reactions should be performed under argon. If excess reagent is used, it should be quenched prior to workup by the cautious addition of methanol. Alternatively, if the use of methanol is incompatible with the products, the reaction mixture may be filtered carefully through a pad of Celite; care must be taken as the residues collected may be pyrophoric. All solvents must be dried and preferably deoxygenated or degassed before use.