Trifluoroacetate compounds hydrogen bonding

Both Si-H and C—H compounds can function as hydride donors under certain circumstances. The silicon-hydrogen bond is capable of transferring a hydride to carbo-cations. Alcohols that can be ionized in trifluoroacetic acid are reduced to hydrocarbons in the presence of a silane. 

For the latter, rate data have been obtained in trifluoroacetic acid-acetic acid media, and the rate versus acidity profiles have been compared to those for compounds (e.g., alkylbenzenes) which do not hydrogen bond significantly. Exchange rates of O- and S-heterocycles relative to alkylbenzenes become progressi vely smaller on going to more acidic media (i.e.,... 

The possible presence in the 4-chloro-4-hexenyl trifluoroacetate of small amounts of two cis-trans pairs of products of addition of trifluoroacetic to the triple bond without concomitant halogen shift remains speculative. In any event these compounds would be removed as ketones upon hydrolysis of the trifluoroacetate. Both the 4-chloro-4-hexenyl trifluoroacetate and the alcohol resulting from its hydrolysis have been shown to contain 9% of the (E) isomer. In the present study the hydrogen decoupled magnetic resonance spectra of the ester and alcohol were shown to contain peaks attributable to approximately 9% of E) isomer. 

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