Categories: N-H Bond Formation >
Reduction of azides
Poly(ethylene glycol) (PEG) (400) has been found to be a superior solvent over ionic liquids by severalfold in promoting the hydrogenation of various functional groups using Adams' catalyst. Both the catalyst and PEG were recycled efficiently over 10 runs without loss of activity, and without substrate cross contamination.
S. Chandrasekhar, S. Y. Prakash, C. L. Rao, J. Org. Chem., 2006, 71, 2196-2199.
Organic azides are easily and chemoselectively reduced to the corresponding amines by reaction with dichloroindium hydride under very mild conditions. γ-Azidonitriles give pyrrolidin-2-imines in an outstanding cyclization.
L. Benati, G. Bencivenni, R. Leardini, D. Nanni, M. Minozzi, P. Spagnolo, R. Scialpi, G. Zanardi, Org. Lett., 2006, 8, 2499-2502.
A selective and facile method allows the reduction of aromatic azides to amines by employing borontrifluoride diethyl etherate and sodium iodide. This methodology has been applied towards the preparation of biologically important imine-containing pyrrolobenzodiazepines and their dilactams through an intramolecular reductive-cyclization process.
A. Kamal, N. Shankaraiah, N. Markandeya, Ch. S. Reddy, Synlett, 2008, 1297-1300.
Aryl azides undergo clean reduction by copper nanoparticles in water in the presence of ammonium formate. The surface hydrogen on copper nanoparticles is considered to be the active reducing species. Various functionalized aryl azides and aryl sulfonyl azides are reduced to the corresponding amines with excellent chemoselectivity in high yields.
S. Ahammed, A. Saha, B. C. Ranu, J. Org. Chem., 2011, 76, 7235-7239.
Ammonia, pyridine and ammonium acetate were extremely effective as inhibitors of Pd/C catalyzed benzyl ether hydrogenolysis. While olefin, Cbz, benzyl ester and azide functionalities were hydrogenated smoothly, benzyl ethers were not cleaved.
H. Sajiki, Tetrahedron Lett., 1995, 36, 3465-3468.
A novel enantioselective synthesis of α-amino acids has been developed, which is broad in scope, simple in application, and advantageous for many α-amino acids of interest in chemistry, biology, medicine.
E. J. Corey, J. O. Link, J. Am. Chem. Soc., 1992, 114, 1906-1908.
(Me3Si)3SiH was successfully used in various radical-based transformations in water. The system comprising substrate, silane, and initiator (ACCN) mixed in aqueous medium at 100°C worked well for both hydrophilic and hydrophobic substrates. In case of water-soluble water-soluble substrates, an amphiphilic thiol was also needed.
A. Postigo, S. Kopsov, C. Ferreri, C. Chatgilialoglu, Org. Lett., 2007, 9, 5159-5162.