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4.4.17.4.3 Method 3: Cleavage of Triisopropylsilyl Ethers with Tris(dimethylamino)sulfur (Trimethylsilyl)difluoride

DOI: 10.1055/sos-SD-004-00380

White, J. D.; Carter, R. G.Science of Synthesis, (20024398.

Tris(dimethylamino)sulfur (trimethylsilyl)difluoride (TASF) as a source of fluoride ion has been used to cleave triisopropylsilyl ethers in situations where the basicity of tetrabutylammonium fluoride would be destructive toward other functionality. An example in which only tris(dimethylamino)sulfur (trimethylsilyl)difluoride could be employed to successfully cleave a triisopropylsilyl ether is seen in the conversion of 76 into baccatin III (78, Scheme 38).[‌81‌] Cleavage of the silyl ether to yield alcohol 77 was followed by treatment with phenyllithium, which removed the 2,2,2-trichloroethoxycarbonyl (Troc) protection and opened the cyclic carbonate en route to triol 78 (accompanied by a 46% yield of 10-O-deacetylbaccatin III).

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