O-r-Butyldimethylsilyl

Diastereomeric mixtures of vicinal nitro alcohols obtained by a classical Henry reaction with low dia-stereoselectivity can be easily silylated to give the corresponding mixture of O-r-butyldimethylsilyl ethers.26 The latter undergoes an enrichment of the erythro isomer (54 up to >95 5) by treatment with LDA and successive protonation of the corresponding lithium salts (Scheme 8), which occurs with high diastereoselectivity. 

The preparation of 3-deoxy-3-trifluoroacetamido-substituted C-2-acyl glycals such as 1 has been achieved by treating either l-O-r-butyldimethylsilyl ethers of appropriate 2-deoxy pyranoses or glycals with acyl chlorides in the presence of aluminium trichloride or ferric chloride. ... 

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