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Cyclopropanation Bingel type adducts

The usefulness of the retro-cyclopropanation reaction is even more remarkable than previously anticipated. It was questioned whether this reaction allowed the selective removal of a Bingel-type addend while leaving addends of a different type unaffected. A variety of mixed bis-adducts such as those shown in Fig. 29, were prepared, all of which contained a bis(ethoxycarbonyl)methano group [182]. In all cases, CPE led to the selective removal of the Bingel addend in over 60% yield, while the other one was retained, confirming that the reaction may be used in a synthetic protection-deprotection protocol to prepare novel fullerene derivatives. [Pg.196]

Figure 1.29. Valence isomerization of a primary C2-symmetric Bingel type hexakis-adduct of C70 with two 6-5 closed bonds (leftside), initially formed in the cyclopropanation of bis-adduct ( )-103 (Figure 1.26), to the more stable C2-symmetric structure ( )-112, containing two 6-5 open bonds. The molecules are viewed along the C2-axis. Figure 1.29. Valence isomerization of a primary C2-symmetric Bingel type hexakis-adduct of C70 with two 6-5 closed bonds (leftside), initially formed in the cyclopropanation of bis-adduct ( )-103 (Figure 1.26), to the more stable C2-symmetric structure ( )-112, containing two 6-5 open bonds. The molecules are viewed along the C2-axis.
Figure 17 Mono (50) and regio-isomeric bis-adducts (51, ( )-52 and ( )-53) formed by Bingel cyclopropanation of [70]fullerene. Also shown are Newman-type projections looking down the C s-symmetry axis of the C70 core on to the two polar pentagons, which show the relative orientations of the addends. Figure 17 Mono (50) and regio-isomeric bis-adducts (51, ( )-52 and ( )-53) formed by Bingel cyclopropanation of [70]fullerene. Also shown are Newman-type projections looking down the C s-symmetry axis of the C70 core on to the two polar pentagons, which show the relative orientations of the addends.

See other pages where Cyclopropanation Bingel type adducts is mentioned: [Pg.162]    [Pg.6]    [Pg.78]   
See also in sourсe #XX -- [ Pg.62 , Pg.63 ]




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