Fully Substituted Pyranones via Quasi-Heterogeneous Genuinely Ligand-Free Migita–Stille Coupling of Iodoacrylates
2015-02-06T00:00:00Z (GMT)
by
Migita–Stille
coupling of (Z)-β-iodoacrylates
with (E)-α-stannyl allylic alcohols to furnish
5-alkylidene-4-substituted-5,6-dihydro-2H-pyran-2-ones
is efficiently catalyzed by 2% Pd black in DMF, while Pd(PPh3)4 is inactive. Heterogeneous Pd released in solution
is most likely responsible for the catalysis. The reaction is applicable
to other substrates, without having to resort to ligands, additives,
and/or solid support for Pd. The resulting pyranones can be rearranged
to fully functionalized pyranones in another single step.
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CC BY-NC 4.0