Categories: C=N Bond Formation >
Synthesis of carbodiimides
An I2/CHP-mediated cross-coupling reaction of isocyanides with readily accessible amines gives carbodiimides in good yields. This metal-free strategy for coupling of isocyanides with amines provides an efficient approach for symmetric and unsymmetric functionalized carbodiimide derivative synthesis under mild conditions.
T.-H. Zhu, S.-Y. Wang, Y.-Q. Tao, S.-J. Ji, Org. Lett., 2015, 17, 1974-1977.
An efficient and mild oxidative desulfurization procedure using o-iodoxybenzoic acid enables the synthesis of carbodiimides starting from easily available 1,3-disubstituted thioureas.
P. S. Chaudhari, P. S. Dangate, K. G. Akamanchi, Synlett, 2010, 3065-3067.
Dehydrosulfurization using a hypervalent iodine(III) reagent enables a simple and efficient preparation of symmetrical and unsymmetrical carbodiimides from the corresponding thioureas. The oxidation afforded carbodiimides in excellent yields and high selectivity. A possible mechanism for the transformation is proposed.
C. Zhu, D. Xu, Y. Wei, Synthesis, 2011, 711-714.
An electrochemical oxidative cross-coupling of amines with aryl and aliphatic isocyanides proceeds without involving any transition-metal catalyst, oxidant, or toxic reagents in an undivided cell to provide carbodiimides in good yields with H2 as the only byproduct. A subsequent optional hydrolysis provides ureas in situ.
B. K. Malviya, P. K. Jaiswal, V. P. Verma, S. S. Badsara, S. Sharma, Org. Lett., 2020, 22, 2323-2327.
Sequential Pd(0)/Fe(III) catalysis enables a rapid and efficient synthesis of aminotetrazoles from aryl azides, isocyanides, and TMSN3. The reaction sequence utilizes a Pd-catalyzed azide-isocyanide denitrogenative coupling to generate an unsymmetric carbodiimide, which reacts with TMSN3 in the presence of FeCl3 in a single pot.
R. S. Pathare, A. J. Ansari, S. Verma, A. Maurya, A. K. Maurya, V. K. Agnihotri, A. Sharon, R. T. Pardasani, D. M. Sawant, J. Org. Chem., 2018, 83, 9530-9537.