Categories: Synthesis of O-Heterocycles > benzo-fused O-Heterocycles >
Synthesis of isochromenes
Recent Literature
An effective, Ru-catalyzed cycloisomerization of benzannulated homo- and
bis-homopropargylic alcohols affords benzofurans and isochromenes chemo- and
regioselectively (5-, and 6-endo cyclizations). The presence of an amine/ammonium
base-acid pair is crucial for the catalytic cycle.
A. Varela-Fernández, C. González-Rodríguez, J. A. Varela, L. Castedo, Carlos Saá, Org. Lett., 2009,
11, 5350-5353.
A versatile and efficient access to 1H-isochromenes via a domino
cycloisomerization/reduction reaction process starting from a wide range of
functionalized ortho-alkynylbenzaldehydes is catalyzed by
dichloro(2-pyridinecarboxylato)gold ([AuCl2(Pic)]).
E. Tomás-Mendivil, J. Starck, J.-C. Ortuno, V. Michelet, Org. Lett.,
2015,
17, 6126-6129.
Gold-catalyzed oxidative cyclizations of o-(alkynyl)phenyl propargyl ether
derivatives enable a convenient synthesis of functionalized 1H-isochromene
and 2H-pyran derivatives via highly regioselective oxidation, followed by
1,2-migration of an enynyl group and nucleophlic addition. Oxidative cleavage of
the exocyclic double bond of the obtained 1H-isochromenes provides
isocoumarins.
J. Zhao, W. Xu, X. Xie, N. Sun, X. Li, Y. Liu, Org. Lett.,
2018, 20, 5461-5465.
A synthesis of 3-substituted-1-alkoxyisochromenes starting from
2-alkynylbenzaldehydes and different alcohols is catalyzed by a silver(I)
complex with an original macrocyclic pyridine-containing ligand. The convenient
approach is characterized by absolute regioselectivity, mild reaction conditions
and good to excellent reaction yields.
M. Dell'Acqua, B. Castano, C. Cecchini, T. Pedrazzini, V. Pirovano, E. Rossi, A.
Caseli, G. Abbiati, J. Org. Chem., 2014,
79, 3494-3505.
