The relative reactivities of acyl compounds towards nucleophilic substitution is acyl chloride> anhydride>ester>amide. I would like to know how this kinetic property is decided. Is it on the basis of better leaving grp or is there another explanation for it?,
It is likely to be due to the different amounts of partial positive charge which exist on the carbonyl carbon.
We can consider for example the rate of reaction of a given amine (such as aniline) with the acid chloride, acid anhydride and an ester such as the methyl ester. The partial positive charge argument would explain this reactivity series.