- High temperatures synthesis of Bowl-shaped subunits of fullerenes - IV. From 4-[9H-fluorenylidene-(9)]-4H-cyclopenta[def]phenanthrene to fluoreno[1,9,8-abcd]corannulene and difluoreno[1,9,8,7-cdefg; 2',1',9',8'-klmno]anthracene
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Fluoreno[1,9,8-abcd]corannulene (4) and difluoreno[1,9,8,7-cdefg;2',1',9',8'-klmno]anthracene (8) have been synthesized by multistage thermal and catalytic dehydrocyclization reactions starting from 4-[9H-fluorenylidene-(9)]-4H-cyclopenta[def]phenanthrene and benzo[p]naphtho[1,8,7-ghi]chrysene, respectively.
- Hagen,Christoph,Zimmermann
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p. 6961 - 6970
(2007/10/02)
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- Structural Studies on Phenanthropyrene and its 9,10-Dihydro-Derivative: Dependence of Chemical Shift on Degree of Planarity of and Buttressing Effect in the Polycyclic Aromatic Compounds
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The first example of a transannular reaction of a syn-metacyclophane derivative via photochemical iodination has been employed in the preparation of 9,10-dihydrophenanthropyrene (2).The structural studies of 2 and the phenanthropyrene 1 were carried out by 1D and 2D NMR spectroscopic analyses.Qualitative correlation between tilting of the fused moieties and the change in deshielding effect was observed by probing the chemical shifts of H3 and H1' (H6 and H8').Buttressing effects resulting from the steric interaction of H3 and H1' (H6 and H8'), althoughdiffering in magnitudes for the two groups of protons (H3->H2->H1->H10 and H1'->H2'->H3'->H4'), seem to transmit evenly among those on the same moiety according to a simple additivity rule.
- Lai, Yee-Hing,Ang, Slau-Gek,Li, Hwee-Chze,Wong, Siew-Ying
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p. 1315 - 1319
(2007/10/02)
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- Use of Bridge Annelation To Retain the Syn Stereochemstry of Metacyclophane Derivatives: A Route to an Elusive syn-Metacyclophanediene
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Free-radical bromination of 9,10-di-m-tolylphenanthrene (6) afforded the anti and syn conformers of the bis(bromomethyl) derivative 7 with the barrier of interconversion estimated at 90 kJ mol-1.Sodium sulfide coupling of 7 suprisingly yielded
- Lai, Yee-Hing,Lee, Siok-Mun
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p. 4472 - 4476
(2007/10/02)
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