Trimethylsilylmethyl phenyl sulfide

Lithiation of (Trimethylsilylmethyl) Phenyl Sulfide and Subsequent Reaction with Acetone... 

A solution of 0.055 mol of butyllithium in 36 ml of hexane and 40 ml of THF are added together with cooling below 0°C. The mixture is cooled to — 10 °C, after which 0.05 mol (9.8 g) of (trimethylsilylmethyl) phenyl sulfide (see Exp. 14) is added. The cooling bath is removed. Above + 5 °C the reaction is markedly exothermic. After the evolution of heat has ceased, the yellow solution is warmed for an additional 10 min at 25 to 30 °C and subsequently cooled to — 60 °C. Dry acetone (0.06 mol, 3.5 g) is added in one portion after the cooling bath has been removed. The temperature of the solution rises within a few s to about 0 °C. After an additional 10 min 50 ml of ice water is added with vigorous stirring. After separation of the layers two extractions with small portions of Et20 are carried out The combined... 

However, TMEDA unlike HMPA, does not cause flow over from a carbonyl to conjugate addition manifold for many lithiated systems. For example, lithiated allylic sulfides undergo conjugate (or 1,4 ) addition to cyclopent-2-enone in the presence of HMPA (see Allyl Phenyl Sulfide), but in the presence of TMEDA, carbonyl addition only is observed. The perception that TMEDA is unable to form solvent-separated ion pairs required for conjugate addition in this case now requires reevaluation. j In the reaction of lithio a-trimethylsilylmethyl phenyl sulfide with cy-clohexenone, HMPA promotes predominant conjugate addition, whereas TMEDA has little effect on the normal carbonyl addition pathway taken in THF alone (eq 8). ... 

AMINATION Azidomethyl phenyl sulfide. Trimethylsilylmethyl azide. 

Phenyl trimethylsilylmethyl sulfide 196.4, b 48 /0.04mm, 113-115 /12mm, 158.5 /52mm, d" " 0.9671, Hq 1.5380. If the sample is suspect then add H2O, wash with 10% aqueous NaOH, H2O again, dry (anhydrous CaCl2) and fractionally distil through a 2ft column packed with glass helices. [J Am Chem Soc 76 3713 1954.]... 

---