Categories: N-H Bond Formation >
Cleavage of imides
Phthalimides are converted to primary amines in an efficient, two-stage, one-flask operation using NaBH4/2-propanol, then acetic acid. Phthalimides of α-amino acids are smoothly deprotected with no measurable loss of optical activity.
J. O. Osby, M. G. Martin, B. Ganem, Tetrahedron Lett., 1984, 25, 2093-2096.
A LiOH-promoted hydrolysis of twisted N-acyl glutarimides provides primary amides under mild conditions at room temperature. In addition, a gram-scale synthesis of a primary amide using a continuous flow method was achieved.
K. Govindan, W.-Y. Lin, Org. Lett., 2021, 23, 1600-1605.
A simple treatment with allyl bromide enables a site-selective cleavage of glutarimides, creating a common platform for accessing a diverse range of nitrogen-containing functional groups such as primary amides, sulfonamides, primary amines, N-acyl compounds (esters, thioesters, amides), and N-sulfonyl esters.
K. Govindan, N.-Q. Chen, Y.-W. Chuang, W.-Y. Lin, Org. Lett., 2021, 23, 9419-9424.
A ruthenium catalyst enables an unprecedented transformation of a wide range of phthalimides into amides in high yields and short reaction time in a single-step. The mechanism involces a unique, homogeneous pathway via five-membered ring opening and CO2 release with water as source of protons.
Y.-C. Yuan, R. Kamaraj, C. Brunaeu, T. Labasque, T. Roisnel, R. Gramage-Doria, Org. Lett., 2017, 19, 6404-6407.