Methylthio trimethylsilane

Shinokubo, H. Oshima, K., Chem. Lett. 2001,956. 

Solubility sol organic solvents (CH2CI2, benzene, acetonitrile, ether). 

Form Supplied in colorless liquid commercially available. 

Handling, Storage, and Precautions the reagent is sensitive to moisture and incompatible with strong oxidizing agents. Should be used in a well-ventilated fume hood. 

Carbonyl Protection. The Lewis acid-catalyzed reaction of aldehydes and ketones with (methylthio)trimethylsilane gives rise to the corresponding thioacetals (eq 1). Selective thioacetalization can be achieved with this reagent (eq 2). The reaction with a,/3-unsaturated aldehydes and ketones leads to the formation of the 1,4-addition product. 

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TiCU, SiCl4, with a disulfide (RSSR R = alkyl or aryl), ° or with methylthio-trimethylsilane (MeSSiMe3). ... 

Methyl 2,4,7,8,9-penta-0-acetyl-Neu5Ac (40 g, 61 mmol) (Methylthio)trimethylsilane (27 g, 225 mmol)... 

Cleavage of Acyclic and Cyclic Ethers. Acyclic ethers are readily cleaved by (methylthio)trimethylsilane (eq 3). In... 

Compound 1 was converted by (1) benzoylation of the remaining hydroxyls, followed by either (2) selective transformation of 2-(trimethylsilyl)ethyl (SE) group at the reducing end into the corresponding P-acetate by treatment [4] with boron trifluoride etherate-acetic anhydride and (3) introduction of the methylthio group by treatment [5] with (methylthio)trimethylsilane and boron trifluoride, or (4) chemo-... 

In this experiment the conditions for the a-lithiation of methyl benzyl sulfide and benzyl trimethylsilane are compared. Whereas the sulfide is readily metallated at very low temperature by BuLi in a THF-hexane mixture, the silyl derivative does not react at all, and even at 0-20°C the metallation proceeds sluggishly. Using the more efficient couple BuLi-TMEDA in hexane, however, a rapid lithiation of the silyl compound can be effected at room temperature under these conditions toluene reacts much more slowly. Thus, a trimethysilyl group activates protons in adjacent positions, but to a much lesser extent than does a methylthio group. 

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