Triisopropylsilyl trifluoromethanesulfonate

1-phenylethanol with 1.3 equiv of TIPS triflate and 2.5 equiv of 2,6-lutidine in CH2CI2 at 0 °C for 2 h provides a 98% yield of a-(triisopropylsilyloxy)ethylbenzene (eq 1).  

Solubility sol most organic solvents, such as pentane, CH2CI2, etc. 

Handling, Storage, and Precautions store under argon at 0°C unpleasant odor reacts rapidly with water and other protic solvents. 

Formations of Enol Silyl Ethers. Aldehydes, ketones, and lactones are readily converted into the corresponding enol TIPS ethers. Reactions of cycloalkanones with 1.1 equiv of TIPS triflate and 1.5 equiv of triethylamine in benzene at 23 °C for 1 h gives 98% yields of the corresponding enol silyl ethers (eq 2).  

Silylation of 2-morpholinones with 1.2 equiv of TIPS triflate and 1.5 equiv of triethylamine in CDCI3 for 2 min provides sUyl ketene acetals, which upon standing at rt undergo Claisen rearrangement to afford pipecolic esters (eq 3).  

Handling, Storage, and Precaution sensitive to free radical sources. 

In the second paper, the reaction was extended to aUcyny-late C-I bonds photolytically by the added intermediacy of hex-abutyldistannane to generate the radical from the iodide. Bromides were inert in this alkynylation, suggesting that this differential reactivity of the two halogens should prove advantageous in synthetic applications. 

The reaction outlined in eq 3, was conducted photolytically in benzene solution, with the benzene presumably scavenging the trilluoromethyl radical, as it is scavenged in eq 2. A dozen examples of iodides were successful in yields generally over 60% and with retention of configuration. These room-temperature examples show the reaction to be compatible with such diverse functionality as free hydroxyl, ester, amide, thiazole, and potential -elimination substrates, and succeeded with primary, secondary, and tertiary iodides. 

The special value of the TIPS group lies in its easy removal (TBAF/25 °C72 h) to make the acetylene available for further substitution. Furthermore, the present availability of the TlPS-protec-ted acetylene triflone should make possible a further exploration of the addition and cycloaddition reactions of the acetylene activated by the strong electron-withdrawing power of the triflone group. 

The TIPS variant in eq 1 is used not only neat on the cyclic C-H substrates THF, tetrahydrothiophene, and cyclohexane, but also in acetonitrile with adamantane, which substituted exclusively at the tertiary C-H (50% yield). Alkynylation was also successful with distal functionality, i.e. R = (CH2)20SiR3 and (CH2)3C1, but the triflone could not be formed with ether functionality closer to the acetylene. 

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GjHjiOjP 116-17-6) see Clodronate disodium (3/t,45)-3-(triisopropylsilyloxy)-4-phenyl-2-azetidinone (C nH2()N02Si 132127-31-2) see Docetaxel triisopropylsilyl trifluoromethanesulfonate (C ()H2 F303SSi 80522-42-5) see Tacrolimus... 

Triisopropylsilyl trifluoromethanesulfonate Methanesulfonic acid, trifluoro-, tris(1-methylethyl)silyl ester (11) (80522-42-5)... 

Preparative Method l,3-bis(TIPS)propyne is prepared in quantitative yield by silylation of 3-lithio-l-triisopropylsilyl-l-propyne with triisopropylsilyl trifluoromethanesulfonate. ... 

Related Reagents. f-Butyldimethylchlorosilane triethylsi-lyl trifluoromethanesulfonate trimethylsilyl trifluoromethane-sulfonate f-butyldimethylsilyl iodide A -f-(butyldimethylsilyl)-W-methyltrifluoroacetamide triisopropylsilyl trifluoromethanesulfonate. 

Related Reagents. r-Butyldimethylchlorosilane f-butyldi-phenylchlorosilane triisopropylsilyl trifluoromethanesulfonate. 

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