Categories: Synthesis of O-Heterocycles >
Synthesis of 2H-pyrans
Recent Literature
Phosphine-catalyzed (3 + 3) annulations between allenoates and
1C,3O-bisnucleophiles provide a facile entry to stable 2H-pyrans which
are greatly challenging targets in organic synthesis. (3 + 2) Annulations can be
achieved with the assistance of base to yield furans.
J. Hu, W. Dong, X.-Y. Wu, X. Tong, Org. Lett., 2012,
14, 5530-5533.
A
one-pot sequence via a Ag(I)-catalyzed propargyl-Claisen rearrangement of easily accessed propargyl vinyl ethers,
followed by a base-catalyzed isomerization, and 6π-oxaelectrocyclization, leads
to the formation of stable 2H-pyrans.
H. Menz, S. F. Kirsch, Org. Lett.,
2006, 8, 4795-4797.
DABCO-catalyzed reactions of α-halo carbonyl compounds with
dimethyl acetylenedicarboxylate (DMAD) at room temperature gave polysubstituted furans and highly functionalized 2H-pyrans in
good yields.
M. Fan, Z. Yan, W. Liu, Y. Liang, J. Org. Chem., 2005, 70, 8204-8207.