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Categories: Synthesis of N-Heterocycles > Lactams

Synthesis of 5,6-dihydro-2-pyridinones

Recent Literature

Regioselective ring closing ene-yne metathesis provided an efficient access to different substituted 1-benzazepine scaffolds. Five- and six-membered lactams were efficiently prepared by ring-closing metathesis affording highly functionalizable compounds.
E. Benedetti, M. Lomazzi, F. Tibiletti, J.-P. Goddard, L. Fensterbank, M. Malacria, G. Palmisano, A. Penoni, Synthesis, 2012, 44, 3523-3533.

A Pd-catalyzed α,β-desaturation of N-protected lactams provides conjugated unsaturated counterparts under mildly acidic conditions at room temperature. The reaction tolerates a wide range of functional groups and shows reactivity complementary to that of prior desaturation methods. Lactams with various ring sizes and substituents at different positions all reacted smoothly.
M. Chen. G. Dong, J. Am. Chem. Soc., 2017, 139, 7757-7760.

An oxidative relay Heck arylation reaction enables the construction of chiral α,β-unsaturated δ-lactams, widely used as pharmacophores, in high yields and excellent enantioselectivities. This strategy also allows facile access to 7-substituted α,β-unsaturated ε-lactam products and δ-lactams.
Q. Yuan, M. S. Sigman, J. Am. Chem. Soc., 2018, 140, 6527-6530.

A Pd-catalyzed arylation of aza-Achmatowicz rearrangement products with arylboronic acids provides 2-aryldihydropyridinones for facile synthesis of highly functionalized 2-arylpiperidines. Key to this arylation is the use of non-phosphine-ligand palladium precatalyst. The utility of 2-aryldihydropyridinones is illustrated by the synthesis of a small collection of 2-arylpiperidines.
G. Zhao, D. P. Canterbury, A. P. Taylor, X. Cheng, P. Mikochik, S. W. Bagley, R. Tong, Org. Lett., 2020, 22, 458-463.

In palladium-catalyzed regioselective [5 + 1] annulation reactions of vinyl aziridines/epoxides with ClCF2COONa, vinyl aziridines/epoxides act as heteroatom-containing five-atom synthons, and commercially available and cheap ClCF2COONa is the carbonyl source. This protocol efficiently provides δ-lactams and δ-lactones in good yields.
D. Zuo, T. Zhang, J. Zhao, W. Luo, C. Wang, P. Li, Org. Lett., 2022, 24, 4630-4634.

A palladium-catalyzed carbonylative [5+1] cycloaddition of N-tosyl vinylaziridines with CO provides α,β-unsaturated δ-lactams in dimethylformamide and β,γ-unsaturated δ-lactams in tetrahydrofuran in very good yields.
T. Zhang, S. Wang, D. Zuo, J. Zhao, W. Luo, C. Wang, P. Li, J. Org. Chem., 2022, 87, 10372-10376.