Trifluoroacetic acid cycloalkenes

The 1,4-diacetoxylation was also extended to the use of other acyl groups than acetyl. Thus, an unsymmetrical 1,4-acetoxy-trifluoroacetoxylation of 1,3-dienes was developed by the use of added trifluoroacetic acid to the acetic acid used as the solvent330. With the use of acetone as the solvent with an added carboxylic acid a general diacyloxylation was obtained and, for example, the 1,4-dibenzoates of 2-cycloalkene-l,4-diols were prepared directly from the corresponding l,3-cycloalkadienes33d. 

Aromatisation of Cycloalkenes with Trifluoroacetic Acid . An Efficacious Aromatisa-tion of Isolongifolene in Trifluoroacetic Acid . Trialkylcyanoborates as Intermediates... 

The reduction of several organic compounds with hydroorganosilane/organic acid systems has been studied in some detail. [544] Trifluoroacetic acid is the best proton donor, but sometimes acetic acid is used. The reduction occurs at 20-60°C, usually without a solvent. After the reaction, the product may be neutralised with base, usually an aqueous solution of sodium hydrogencarbonate, separated and distilled. The formation of a carbonium ion is decisive for the reduction of alkenes and cyclo alkanes, and this is more difficult when the alkene chains are straight. Alkenes and cycloalkenes which do not have a C substituent on the double bond do not react. The final products do not include esters of trifluoroacetic acid [545] (Scheme 4.1) ... 

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