Categories: Synthesis of O-Heterocycles > benzo-fused O-Heterocycles >
Synthesis of Chromanones and Flavanones
Recent Literature
A cationic Ru-H complex is a highly effective catalyst for a mild deaminative
coupling reaction of 2'-hydroxyaryl ketones with simple amines to form
3-substituted flavanone products. The analogous deaminative coupling reaction of
2-aminobenzamides with branched amines directly formed 3,3-disubstituted
quinazolinone products.
K. Gnyawali, P. T. K. Arachchige, C. S. Yi, Org. Lett., 2022, 24,
218-222.
A facile ethylenediamine diacetate (EDDA)-catalyzed one-pot reaction of
2-hydroxyacetophenones, aromatic aldehydes, and aniline provides a rapid access
to biologically interesting flavanone derivatives via a Mannich-type reaction.
To demonstrate this method, several biologically interesting natural products
bearing a flavanone moiety were synthesized.
S. V. N. Vuppalapati, L. Xia, N. Edayadulla, Y. R. Lee, Synthesis, 2014, 46,
465-474.
A N-heterocycle carbene (NHC)-catalyzed dual Stetter cascade reaction
enables a coupling of β-nitrostyrene with phthalaldehyde under mild conditions
to furnish valuable aryl-naphthoquinones, whereas the reaction of
salicylaldehydes with β-nitrostyrene provides functionalized
dihydroisoflavanones.
R. N. Mitra, K. Show, D. Barman, S. Sarkar, D. K. Maiti, J. Org. Chem., 2019, 84,
42-52.
DBU catalyzes a sequence of 1,4-conjugate addition of water to alkynyl o-quinone
methide (o-AQM), followed by an alkyne-allene isomerization and
subsequent intramolecular oxa-Michael addition to provide a broad range
of flavanones in very good yields with good functional-group tolerance.
X. He, M. Xie, R. Li, P. Y. Choy, Q. Tang, Y. Shang, F. Y. Kwong,
Org. Lett., 2020, 22, 4306-4310.
A broad range of flavanones were synthesized in very good yields via a
palladium-catalyzed dehydrogenation of chromanones followed by arylation with
arylboronic acids. This reaction provides a route to interesting natural
products such as naringenin trimethyl ether.
H.-S. Yoo, S.-H. Son, Y. Y. Cho, S. J. Lee, H. J. Jang, Y. M. Kim, D. H. Kim, N.
Y. Kim, B. Y. Park, Y. S. Lee, N.-J. Kim, J. Org. Chem., 2019, 84,
10012-10023.
An N-Heterocyclic carbene efficiently catalyzed an intramolecular
nucleophilic substitution reaction to yield benzopyrones and benzofuranones
depending on the substitution pattern.
J. He, J. Zheng, J. Liu, X. She, X. Pan, Org. Lett.,
2006, 8, 4637-4640.
A borane catalyst generated in situ by hydroboration of pentafluorostyrene with
HB(C6F5)2 enables a Piers-type hydrosilylation
of chromones and flavones to afford a variety of chromanones and flavanones in
very good yields.
X. Ren, C. Han, X. Feng, H. Du,
Synlett, 2017, 28, 2421-2424.
An electrochemical synthesis of flavanones via oxa-Michael addition using silver
electrode as a sacrifice offers good yields, broad substrate scope, and good
functional group tolerance. Additionally, the method proved to be applicable on
a gram-scale.
W. A. B. Santos, P. P. de Castro, F. R. Xavier, A. L. Braga, G. M. Martins, S.
R. Mendes, Synthesis, 2023,
55, 1451-1459.
Visible-light mediates a dual acylation of alkenes for the construction of
3-substituted chroman-4-ones in good yields via a radical tandem cyclization
reaction. The reaction involves a carbon-carbon bond cleavage of oxime esters by
a nitrogen-centered radical strategy.
Y.-C. Liu, P. Chen, X.-J. Li, B.-Q. Xiong, K.-W. Tang, P.-F. Huang, J. Org. Chem., 2022, 87,
4263-4272.
Chiral triazolium salts based on the camphor scaffold are highly efficient
catalysts for the asymmetric intramolecular Stetter reaction. With a catalyst
loading of 10 mol%, the desired products were obtained in excellent yields with
up to 97% ee.
Z.-Q. Rong, Y. Li, G.-Q. Yang, S.-L. You, Synlett, 2011,
1033-1037.
The first enantioselective intramolecular catalytic Stetter reaction, which
opens up a short and efficient pathway to enantiomerically enriched
chroman-4-ones, is reported.
D. Enders, K. Breuer, J. Runsink, Helv. Chim. Acta, 1996, 79, 1899-1902.
A highly enantio- and diastereoselective intramolecular Stetter reaction has
been developed. Aliphatic and aromatic aldehydes and a broad range of
trisubstituted Michael acceptors have been found to afford the desired
products in good overall yield with high enantio- and diastereoselectivity.
J. Read de Alaniz, T. Rovis, J. Am. Chem. Soc.,
2005, 127, 6284-6289.
A Rh-catalyzed highly chemo- and enantioselective hydrogenation of 2-CF3-chromen-4-ones
provides chiral 2-CF3-chroman-4-ones with excellent
enantioselectivities and high turnover numbers. The catalyst was also suitable
for the reduction of 2-CF3-thiochromen-4-ones. The obtained
hydrogenation products were also successfully transformed into other derivatives.
C. Xie, Q. Guo, X. Wu, W. Ye, G. Hou, J. Org. Chem., 2023, 88,
15726-15738.
N-Heterocyclic carbenes (NHCs) catalyze a highly enantioselective
synthesis of fluoroalkylated benzopyranones and 3-coumaranones with all-carbon
quaternary stereocenters via annulation reactions between in situ generated acyl
anion intermediates and highly substituted trifluoromethyl-β,β-disubstituted
Michael acceptors. The method can also be extended to perfluoroalkyl homologues.
I. Barańska, K. Rafińska, Z. Rafiński, J. Org. Chem., 2023, 88,
14339-14344.