Chemistry Reference
In-Depth Information
Following proton transfer, the resulting carboxylate anion adds to the protonated
dicyclohexylcarbodiimide.
Like the mixed carbonic anhydride (intermediate A from Problem 7(a)),
intermediate B is an active ester that can react with amines to form amides. The
addition-elimination mechanism, illustrated below using arrow pushing, involves
addition of an amine followed by elimination of dicyclohexylurea.
Like Problems 7(a) and 7(b), the first step of this reaction is a proton transfer. In
this case, the basic nitrogen is a nitrogen atom present on carbonyl diimidazole.
Following proton transfer, the carboxylate anion participates in an addition-
elimination reaction where the carboxylate anion adds to the carbonyl of carbonyl
