Dicyclohexylcarbodiimide (DCC) has the following structure:
__ __
/ \ / \
\__/\ /\__/
N=C=N
This
molecule is the most general
reagent for the formation of
peptide bonds, which are the connecting bonds in
polypeptides between
amino acids. The mechanism of formation of the
peptide bond is, the
amino acid (or
polypeptide) with a
deprotected C-
terminus attacks the
carbon in the DCC, forming an O-
acyl isourea. The structure is the same as the structure above, except one of the C=N double bonds is moved to the
oxygen of the C-terminus of the amino acid or polypeptide. All that happens as a result is, the C-terminus is more
reactive, and so the formation of the peptide bond is made possible. The DCC is then kicked off, but as an N,N'-
dicyclohexyl urea.
I'm not sure where to go for better information on DCC, but for more information on
polypeptide synthesis in general, refer to the
polypeptide node. This information is
derived from
synthesis of information presented in
Organic Chemistry: Structure and Function by Vollhardt and Schore, and
lectures given by Professor
Eric T. Kool at
Stanford Uniiversity.