The substitution of all electronegative substituents in trichloroacetonitrile by nucleophilic attack of alkoxide anions produces orthocarbonic acid esters in high yield.
Due to the high reactivity of the chlorine atoms, trichloroacetonitrile can be used (especially in combination with triphenylphosphine) to convert allylic alcohols into the corresponding allylic chlorides.
With carboxylic acids, acyl chlorides are obtained.
Due to the mild reaction conditions, the ClCCN/PPh system is also suitable for the activation of carboxylic acids and their linkage with supported amino compounds to amides (peptides) in solid-phase syntheses. From sulfonic acids, the corresponding sulfochlorides are formed analogously. In an analogous manner, the activation of diphenylphosphoric acid with ClCCN/PPh and reaction with alcohols or amines proceeds to the corresponding phosphoric acid esters or amides in a gentle and efficient one-pot reaction.
Also, phenolic hydroxy groups in nitrogen-containing aromatics can be converted into the chlorine compounds.
In a Hoesch reaction, aromatic hydroxyketones are formed in the reaction of substituted phenols with trichloroacetonitrile, for example from 2-methyl phenol the 2-trichloroacyl derivative in 70% yield.
The electron-withdrawing effect of the trichloromethyl group activates the nitrile group of trichloroacetonitrile for the attack of nucleophilic oxygen, nitrogen and sulfur compounds. For example, alcohols give O-alkyltrichloroacetimidates under basic catalysis in a direct and reversible addition, which can be isolated as stable and less hydrolysis-sensitive adducts.
With primary and secondary amines, N-substituted trichloroacetamidines are formed in a smooth reaction with good yields, which can be purified by vacuum distillation and are obtained as colorless, malodorous liquids. Reaction with ammonia and then with anhydrous hydrogen chloride gives the solid trichloroacetamidine hydrochloride, the starting compound for the fungicide etridiazole.
In academic research, trichloroacetonitrile is used as a reagent in the Overman rearrangement, converting allylic alcohols into allylic amines. The reaction is based on a [3,3]-sigmatropic and diastereoselective rearrangement.
Benzyl trichloroacetimidate is easily accessible from benzyl alcohol and trichloroacetonitrile. Benzyl trichloroacetimidate is useful as a benzylating reagent for sensitive alcohols under mild conditions and to preserve chirality.