Fluorous alcohol protective group

A highly fluorous alkoxy ethyl ether was synthesized and used as a protective group of alcohols. Treatment of an ether solution of 1 equivalent of a primary alcohol and 3 equivalents of the fluorous vinyl ether 29 with 5 mol% of camphorsulfonic acid (CS A) for 3 h at room temperature provided the desired protected alcohols 30 in 84-93% yields (Scheme 33). The products and the excess fluorous vinyl ether were extracted with FC-72 and then separated by column chromatography. Secondary and even tertiary alcohols were similarly protected in good yields in THF at 65°C for 30 5 min. The protected fluorous acetals were treated in a 1 1 solution of ether and methanol with 5 mol% of CSA for 1 h for deprotection. After completion of the reaction, the products were isolated in pure form by simple three-phase extraction (reaction mixture/saturated aqueous NaHC03/FC-72). 

Fluorous tertiary alcohols were prepared and applied as protecting groups of carboxylic acids. The fluorous alcohols were reacted with phenylacetic acid and... 

Scheme 8.1 Fluorous tags and protecting groups for alcohol and diol used in oligosaccha-ride synthesis.

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