jo8b01075_si_001.pdf (127.89 MB)
Download fileTotal Synthesis of Spiromamakone A and Structure Revision of Spiropreussione A
journal contribution
posted on 2018-06-13, 00:00 authored by Hirokazu Tsukamoto, Shogo Hanada, Yumi Nomura, Takayuki DoiSpiromamakone
A is a racemic natural product having a naphthyl
acetal group on a spiro[4,4]nonadiene skeleton. Its total synthesis
was achieved by double oxa-Michael addition of 1,8-dihydroxynaphthalene
to 2-(1-bromoalkylidene)-4-isopropoxy-4-cyclopentene-1,3-dione, which
was prepared by palladium(II)-catalyzed ring expansion of 4-(1-alkynyl)-4-hydroxy-3-isopropoxy-2-cyclobuten-1-one,
and a subsequent intramolecular aldol reaction. The synthesis using
optically active intermediates enabled identification of the racemization
step of spiromamakone A and revealed that spiromamakone A and spiropreussione
A are identical; the latter had been reported as a constitutional
isomer of the other.