| Summary: | 博士 === 國立中正大學 === 化學研究所 === 99 === Various synthetic methods of benzocoumarins are described in this study.
In chapter 2, we have developed a new and useful method of preparing 5,6-benzocoumarins (2–2g) with different substituents on a variety of positions. Their molecular skeletons were formed from the oxidation of 2H-pyrans by DDQ reagent. These 2H-pyrans were prepared by tandem reaction of cis-hydrogenation of enynals and electrocyclization. Various α-tetralones were used as starting materials. Heteroarene-fused coumarins (2h–2k) were also prepared respectively.
In chapter 3, a modified synthetic route – α-tetralone keto ester was catalyzed by DBU– for Michael addation is described. The results
not only represent sizable yield of 7,8-benzocoumarins (3–3g, 22b, 22c, 26) under convenient conditions, but also provide an efficient route for the synthesis of some natural products, such as Angelicin (28), Seselin (33), and Pyrone (39, 39d).
In chapter 4, a new benzocoumarin building block method from β-tetralone has been discovered, under the condition of propiolic acid and HOTf, to give Claisen rearrangement products. The 5,6-benzocoumarin carbon skeleton from substituted β-tetralone was built up in 2 steps.
In final chapter, previous reaction condition was carried out naphthols and meta-substituted phenols. Aromatic coumarins (63–79) and some natural products (83, 87) were prepared respectively.
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