Abstract
The synthesis of kynapcin-24, which can be isolated from the
Korean mushroom Polyozellus multiflex Murr,
is achieved in 12% overall yield from commercially available
3,4-dihydroxybenzaldehyde by a route in which the longest linear
sequence is only 14 steps. The key transformations in the synthesis
are copper-mediated and palladium-catalyzed coupling reactions of
the iodide 3-iodo-5,6-diisopropoxy-2-[(tetrahydropyran-2-yloxy)methyl]benzofuran
with the corresponding stannane 5,6-diisopropoxy-2-[(tetrahydropyran-2-yloxy)methyl]-3-(tributylstannyl)benzofuran,
and a 5-endo -dig iodocyclization
of a (hydroxyphenyl)propargyl ether.
Key words
kynapcin-24 - copper-mediated - palladium-catalyzed - coupling - cyclizations
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