R-Butyldimethylsilyl chloride

This triflate has been prepared by reaction of r-butyldimethylsilyl chloride with silver triflate (expensive)1 or triflic acid (80% yield).2 Since this triflate is sensitive to moisture, it should be used soon after preparation. In combination with 2,6-lutidine, it converts even tertiary alcohols into r-butyldimethylsilyl ethers in 70-90% yield. 

Ethyl l-thio-/3-lactoside (79) Acetal THF Amb. r-Butyldimethylsilyl chloride 0 0 6 96 86... 

Methyl 2,6-dideoxy-a-D-/yxo- Acetal Toluene TBAB 80 r-Butyldimethylsilyl chloride — 85 0 178... 

Ynol tosylates are synthesized from terminal alkynes via a unique sequence (equation 10). The hypervalent organoiodine compound 32, prepared by treatment of iodosoben-zene diacetate with /i-toluenesulfonic acid, reacts with the terminal alkynes 31 to give the iodonium tosylates 33, which are then treated with 10 mol% of CuOTf or AgOTf to afford the ynol tosylates 34. Finally, the ynol tosylates 34 are converted into lithium ynolates 35 by treatment with MeLi. The ynolates are trapped with r-butyldimethylsilyl chloride, triethylgermyl chloride and tributylstannyl chloride to give the silyl ynol ethers 36, the germyl ketenes 37 and the stannyl ketene 38. ... 

A more stable, and consequently more synthetically useful protecting group, is the tert-butyldimethylsilyl (TBS) functionality. Ethyl or methyl lactate is easily protected with this group by treatment with r r -butyldimethylsilyl chloride in the presence of a suitable base. The use of imidazole in DMF furnishes 401 or 402 in 90-99% yield [126,127,128,130], whereas triethylamine/DMAP in tetrahydrofuran affords 401 in 90% yield [129]. 

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