t-Butyldimethylsilyl Iodide


[72726-45-5]  · C6H15ISi  · t-Butyldimethylsilyl Iodide  · (MW 242.17)

(reagent capable of converting oxiranes into hydrolytically stable allylic silyl ethers, which can then be converted into their corresponding allylic alcohols without rearrangement1-3)

Alternate Name: TBDMSI.

Physical Data: mp 53-60 °C dec.2

Solubility: sol most organic solvents.

Handling, Storage, and Precautions: should be used as prepared.

t-Butyldimethylsilyl iodide (TBDMSI) is typically generated in situ by the treatment of (phenylseleno)-t-butyldimethylsilane with 0.5 equiv of Iodine in acetonitrile.1,2 It is then used as prepared owing to the instability of the pure form.1

A wide variety of hydrolytically stable allylic silyl ethers can be easily prepared from oxiranes using this reagent. Oxiranes react with TBDMSI in acetonitrile at 0 °C to form silylated halohydrins. These were then isolated and reacted with 1,5-Diazabicyclo[4.3.0]non-5-ene (DBN) in refluxing THF to afford the desired allylic silyl ethers.1,2 The net change in this sequence is the conversion of oxiranes into allylic alcohols (eqs 1-4).

The protecting group can be removed by treatment of the allylic silyl ethers with Tetra-n-butylammonium Fluoride in moist DMSO or THF. Desilylation may also be accomplished by the use of Potassium Fluoride in the presence of a catalytic amount of 18-Crown-6.1,2

Related Reagents.


1. Detty, M. R. JOC 1980, 45, 924.
2. Detty, M. R.; Seidler, M. D. JOC 1981, 46, 1283.
3. Detty, M. R.; Seidler, M. D. TL 1982, 25, 2543.

Nicholas J. Sisti

SmithKline Beecham Pharmaceuticals, King of Prussia, PA, USA

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