Studies on the sesquiterpenoids of hypolepis punctata mett.—II
作者:Yuji Hayashi、Mugio Nishizawa、Takeo Sakan
DOI:10.1016/0040-4020(77)80074-4
日期:1977.1
Hypacrone (1), a new seco-illudoid, was synthesized by several steps, including a cross aldol condensation of two major moieties, a diketone (2) and a cyclopentenone derivative (11).
Ozonolyses of 4,4-Dimethyl-2-cyclohexen-1-yl Acetate and 4,4-Dimethyl-2-cyclopenten-1-yl Acetate. Competition between the Steric Effects of the Allylic Methyl Groups and the Electronic Effects of the Acetoxy Group on the Direction of Cleavage of the Primary Ozonides
In order to understand the relative directing effects of the substituent steric and electronic effects on the cleavage of the primary ozonides, ozonolyses of a series of cyclohexene and cyclopentene derivatives were conducted in methanol or in ether in the presence of trifluoroacetophenone. The ozonolysis of 4,4-dimethyl-2-cyclohexen-1-yl acetate (1k) in methanol provided exclusively the alpha-methoxyalkyl hydroperoxide 7k derived from capture of 5-acetoxy-5-formyl-2,2-dimethylpentanal oxide by the solvent, while in the case of the relevant 4,4-dimethyl-2-cyclopenten-1-yl acetate (1l) the solvent-captured product 6l derived from trapping of 2-acetoxy-5-formyl-5-methylpentanal oxide was the major product. The remarkable difference in the regiochemistry of the fragmentation between the primary ozonides, 2k and 2l, is rationalized in terms of the significant difference in the steric congestion.
Catalytic isomerization of water-soluble quadricyclane to norbornadiene derivatives induced by cobalt-porphyrin complexes
作者:Kazuhiro Maruyama、Hitoshi Tamiaki
DOI:10.1021/jo00355a006
日期:1986.3
Eilbracht,P.; Dahler,P., Liebigs Annalen der Chemie, 1979, p. 1890 - 1907
作者:Eilbracht,P.、Dahler,P.
DOI:——
日期:——
Synthesis of 7,7-dimethylnorbornadiene
作者:Charles W. Jefford、Timothy W. Wallace、Nguyen Thi Huong Can、Christian G. Rimbault