88958-98-9Relevant academic research and scientific papers
SYNTHESIS, STRUCTURE AND REACTIVITIES OF PARACYCLOPHANES
Tobe, Yoshito,Ueda, Ken-ichi,Kakiuchi, Kiyomi,Odaira, Yoshinobu,Kai, Yasushi,Kasai, Nobutami
, p. 1851 - 1858 (2007/10/02)
The synthesis, structure and reactivities of paracyclophanes 2a-c, the smallest bridged paracyclophanes so far isolated, are described.The parent hydrocarbon 2a has been efficiently synthesized by oxidative decarboxylation of propellenecarboxylic acid (7) by lead tetraacetate.The 8-carbomethoxy derivative 2b has been quantitatively synthesizedby thermal valence isomerization of the propelladiene (4b) (Dewar isomer of 2b).X-Ray structure analysis of the crystalline 2c has revealed that the benzene ring of 2c is severely deformed into a boat conformation with deformation angles of α=20.5 degree and β=18.5 degree.Furthermore, the bond angles of the bridging chain (C(2), C(3), C(4) and C(5)) are considerably expanded from the normal sp3 angle.Vapor phase thermolysis of 2a gives the spiro triene 12 via homolysis at the benzyl position.Acid-catalyzed isomerization of 2a with trifluoroacetic acid takes place readily to afford the meta and ortho isomers 13a and 14a in a ratio of 1:3.UV irradiation of the ester 2b brings about valence isomerization to the Dewar isomer 4b which izomerizes slowly to the prismane derivative 15a on further irradiation.A cycloaddition of 2a with N-phenyl-1,2,4-triazoline-3,5-dione occurs at room temperature to give mainly adduct 16.Addition of bromine to 2a takes place to furnish quantitatively the unstable 1,4-addition product 18.Oxidation of 2a with mCPBA readily takes place to give the dienone dimer 20 which affords on UV irradiation the cage diketone 21 derived from intramolecular photocycloaddition.
A NEW EFFICIENT SYNTHESIS AND REARRANGEMENTS OF PARACYCLOPHANE
Tobe, Yoshito,Ueda, Ken-ichi,Kakiuchi, Kiyomi,Odaira, Yoshinobu
, p. 1645 - 1646 (2007/10/02)
paracyclophane (1) has been synthesized by oxidative decarboxylation of propellenecarboxylic acid with lead tetraacetate.Vapor phase thermolysis of 1, affords 3-methylenespiroundeca-1,4-diene predominantly, while acid-catalyzed rearrangement of 1 gives the meta and ortho isomers in ratio of 1:3.
