Categories: Synthesis of O-Heterocycles > benzo-fused O-Heterocycles >
Synthesis of Isochromanones
Recent Literature
An easily prepared recyclable TEMPO derived sulfonic salt catalyst, and
mineral acids (NaNO2 and HCl) enable a selective aerobic oxidation of
structurally diverse benzylic sp3 C-H bonds of ethers and alkylarenes
to provide synthetically and biologically valued isochromanones and xanthones in
good yields.
Z. Zhang, Y. Gao, Y. Liu, J. Li, H. Xie, H. Li, W. Wang, Org. Lett.,
2015,
17, 5492-5495.
A palladium-catalyzed reaction of alkyl 2-vinylbenzoates with silyl-protected
alkynyl bromides provides 3-alkynylated isochroman-1-ones. The use of an alkyl
ester group as an oxygen nucleophile is crucial for an efficient
1,1-alkynyloxygenation.
Y. Ano, S. Takahashi, N. Chatani, Org. Lett., 2023, 25,
3266-3270.
A cyanide-catalyzed ring-expansion of cyclic α-hydroxy-β-oxoesters provides
δ-valerolactone derivatives in up to quantitative yields. Several
alkyl-substituted as well as benzo- and heteroarene-annulated starting materials
are converted without problems. As an additional benefit, the substrates are
straightforwardly accessed by cerium-catalyzed aerobic α-hydroxylation of
readily available β-oxoesters.
D. Kieslich, J. Christoffers, Org. Lett., 2021, 23,
953-957.
A highly stereoselective one-pot intramolecular Mannich reaction using
2-oxopropyl-2-formylbenzoates and anilines as substrates, catalyzed by a
secondary amine, provides 4-aminoisochromanones bearing two adjacent
stereocentres in good yields with excellent cis-stereoselectivities and
ee values.
F. Vetica, J. Fronert, R. Puttreddy, K. Rissanen, D. Enders, Synthesis, 2016,
48, 4451-4458.
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