1075-22-5Relevant articles and documents
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Arnold,Craig
, p. 2791 (1948)
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Iodizing and chlorination of methyl-substituted cis-bicyclo[4.3.0]none-3,7-dienes
Andreyev,Bakhtin,Lukovskaya,Pekhk,Bobyleva,Anfilogova,Belikova
, p. 146 - 153 (2007/10/02)
The direction of halogenation of methyl-substituted cis-bicyclo[4.3.0]none-3,7-dienes depends considerably on the position of the methyl group. For a hydrocarbon without a substituent at C-3, the reaction proceeds with retention of the initial structure, whereas in the case of 3-methyl-substituted dienes it is accompanied by transannular cyclization with the formation of compounds of the brexane type.
Anodic Oxidation of α-Substituted p-Xylenes. Electronic and Stereoelectronic Effects of α-Substituents in the Deprotonation of Alkylaromatic Radical Cations
Baciocchi, Enrico,Mattioli, Mario,Romano, Roberta,Ruzziconi, Renzo
, p. 7154 - 7160 (2007/10/02)
The effect of α-substituents on the deprotonation rate from the benzylic position of alkylaromatic radical cations, k(CH2Z)/k(CH3), has been investigated by determining the intramolecular selectivity in the anodic oxidation in acetic acid of a α-Z-substituted p-xylenes 1 (Z = H, OMe, OH, Me, tert-butyl, OAc, COOMe, CN), 5,6-dimethylindan 4 (R = H), and 2,2,5,6-tetramethylindan 4 (R = Me).Some oxidations induced by CAN have also been carried out.It has been found that, with the exception of when Z = tert-butyl, the deprotonation rate of 1.+ is always faster from the CH2Z group than from the CH3 group, independently of the electron-donating or electron-withdrawing nature of Z.The electron-donating groups (OH, OMe, Me), however, exert a larger effect than the electron-withdrawing ones (COOMe, CN).The negligible deprotonation rate from CH2-t-Bu has been ascribed to stereoelectronic effects (the bulky tert-butyl group does not allow the C-H bonds to be collinear with the ?-system), the suggestion being nicely confirmed by the observation that the deprotonation rate from the position 1(3), relative to that from the 5(6)-methyl group, is almost identical in the radical cations of 4 (R = H and Me).The effect of the other α-substituents is mainly of electronic nature and has been rationalized on the basis of a variable transition-state structure for the deprotonation process.It is suggested that with +R groups most of the charge, in the transition state, has been transferred to the Cα-H bond where it can be stabilized by the α-substituent.With electron-withdrawing groups less charge transfer has taken place and the rate-enhancing effects of these groups is ascribed to their capability to significantly decrease the strength of the Cα-H bond.