Acyl fluorides hydrides

Acylation (see also Acetylation, Cathylation) Acyl fluorides. Benzoylchloride (see Hippuric acid, preparation). N-Carbonylsulfamic acid chloride. Chloroacetic anhydride. Chloroacetyl chloride. Magnesium. Mesyl chloride. Methanesulfonic anhydride. 1-Morpholinocyclo-hexene. Pyridine. Sodium diisopropylamide. Sodium hydride. Trifluoroacetic anhydride. 

As mentioned above, thiazolidine-4-carboxylic acid is characterized by an anomalously low basicity and thus difficult acylation in peptide synthesis. 189 Therefore, the incorporation of this amino acid residue into a growing peptide chain is preferentially preformed via dipeptide derivatives. 139 Suitably N-protected amino acids are coupled directly to the thiazolidine-4-carboxylic acid by the acid fluoride 139 or iV-carboxyan hydride 1392111 methods. The resulting dipeptides are used as building blocks without risk of racemization 139 and standard coupling procedures are applied as pentachlorophenyl esters prepared by the mixed anhydride procedure 121 or PyBOP. 171 ... 

Hydride transfers are implicated in several acylations of alkynes by saturated acyl chlorides leading to cyclopentenes. Intramolecular [1,5] hydride shifts have been shown to be a common feature in silver-assisted reactions of cyclohexanylcarbonyl chloride with alkynes.The nature of the final product depends on the structure of the resulting cation. Capture of fluoride ion, ring contraction and acyl or alkyl migrations of axial substituents have been observed (Scheme 24). 

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