TIPS-acetylene triflone

Alternate Name TIPS-acetylene triflone or TIPS-ethynyl triflone. Solubility most aprotic organic solvents. 

The special value of the TIPS group lies in its easy removal (TBAF/25 °C/2 h) to make the acetylene available for further substitution. Furthermore, the present availability of the TIPS-protected 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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