| Summary: | 博士 === 國立中正大學 === 化學暨生物化學研究所 === 105 === Abstract:
This thesis describes the total syntheses of tetrangulol,
anhydrolandomycinone, parimycin and schisansphenin B.
In the first topic, we developed a simple method to synthesize
angucyclinones; The Diels–Alder reaction of juglone with various styrenes
in the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) was
promoted by B(OAc)3 at room temperature. The reaction proceeded
smoothly and gave the products in 32%~82% yield and with excellent
regioselectivity. We successfully applied this methodology to the total
syntheses of tetrangulol and anhydrolandomycinone from Omethylnaphthazarin
(56) and bromostyrene 7m in 4 synthetic steps with
53% overall yield and 4 synthetic steps with 42% overall yield, respectively.
In the second topic, the first total synthesis of parimycin was
accomplished from O-methylnaphthazarin (56) in 10 synthetic steps. The
key steps in this synthesis were B(OAc)3-promoted intermolecular Diels-
Alder reaction of (56) and diene 108, DMSO-iodine-promoted oxidative
cyclization, and sodium dithionite reduction.
In the third topic, the synthetic study of schisansphenin B was
commenced with 1,3-cyclopentadione in 7 steps. The key steps in this
synthesis were redox-relay Heck coupling reaction of alkene and triflate,
intramolecular Stetter reaction and Tiffeneau-Demjanov-type ring
expansion to construct the spiro[4.5]decane skeleton.
Key words: Diels-Alder reaction、B(OAc)3、Juglone、Styrene、Heck
coupling reaction、Intramolecular Stetter reaction、Spiro.
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