Categories: Synthesis of N-Heterocycles > benzo-fused N-Heterocycles >
Synthesis of dihydroquinolinones
Recent Literature
The combination of SmI2/H2O/MeOH promotes a selective
reduction of quinolin-2(1H)-ones to afford 3,4-dihydroquinoline-2(1H)-ones
under mild conditions with good to excellent yields.
D. Xie, S. Zhang, J. Org. Chem., 2022, 87,
8757-8763.
A Rh/Pd/Cu catalyst system led to an efficient one-pot synthesis of
dihydroquinolinones without any intermediate workup. The conjugate-addition/amidation/amidation
reaction sequence is highly modular, divergent, and practical.
L. Zhang, L. Sonaglia, J. Stacey, M. Lautens, Org. Lett., 2013,
15, 2128-2131.
With the proper choice of palladium catalyst, ligand, and base, five-, six-, and
seven-membered rings are formed efficiently from secondary amide or secondary
carbamate precursors.
B. H. Yang, S. L. Buchwald,
Org. Lett., 1999, 1, 35-37.
[Ru(p-cymene)(L-proline)Cl] catalyzes a cyclization of
1,4,2-dioxazol-5-ones to form dihydroquinoline-2-ones in excellent yields with
excellent regioselectivity via a formal intramolecular arene C(sp2)-H
amidation. The reactions of the 2- and 4-substituted aryl dioxazolones proceed
initially through spirolactamization via electrophilic amidation at the arene
site.
W. Sun, C.-H. Ling, C.-M. Au, W.-Y. Yu, Org. Lett., 2021, 23,
3310-3314.
A metal- and additive-free photoredox cyclization of N-arylacrylamides
provides dihydroquinolinones in good yields in the presence of the organic
light-emitting molecule 4CzIPN as photocatalyst.
Z. Liu, S. Zhong, X. Ji, G.-J. Deng, H. Huang, Org. Lett., 2022, 24,
349-353.
The P-chiral monophosphorus ligand BI-DIME enables an efficient,
palladium-catalyzed, decarboxylative [4 + 2]-cycloaddition of 4-vinyl
benzoxazinanones with carboxylic acids to provide structurally diverse
3,4-dihydroquinolin-2-ones bearing two contiguous stereogenic centers in good
yields with very good stereoselectivities.
J.-H. Jin, H. Wang, Z.-T. Yang, W.-L. Yang, W. Tang, W.-P. Deng, Org. Lett.,
2018, 20, 104-107.
A Pd/chiral Lewis base relay catalysis enables a highly enantioselective
cascade carbonylation/annulation of benzyl bromides, CO, and vinyl
benzoxazinanones under mild conditions to assemble chiral diydroquinolinones from
readily available starting materials in good yields with excellent diastereo-
and enantioselectivities.
W.-W. Ding, Y. Zhou, Z.-Y. Han, L.-Z. Gong, J. Org. Chem., 2023, 88,
5187-5193.
In an asymmetric [4+2] cycloaddition of vinyl benzoxazinanones with a variety
of ketene intermediates via sequential visible-light photoactivation and
palladium catalysis, the traceless and transient generation of ketenes from
α-diazoketones through visible-light-induced Wolff rearrangement is important
for the success of the palladium catalysis.
M.-M. Li, Y. Wei, J. Liu, H.-W. Chen, L.-Q. Lu, W.-J. Xiao, J. Am. Chem. Soc., 2017,
139, 14707-14713.
DBU mediates a formal [4+2] annulation reaction of aza-ortho-quinone
methides (generated from o-chloromethyl anilines) with enolates (formed
from azlactones) to provide biologically significant 3,4-dihydroquinolin-2(1H)-one
derivatives in good yields. This reaction offers use of readily accessible
starting materials, broad substrate scope, and mild reaction conditions.
H. Ji, C. He, H. Gao, W. Fu, J. Xu, Synthesis, 2021, 53,
1349-1355.