Phenanthrene, nucleophilic methylation

There are a few other examples of the Sn reactiOTis in the series of unactivated arenes, such as nucleophilic methylation of anthracene and phenanthrene by action of dimethyl sulfoxide (DMSO) in the presence of a strong base (sodium hydride or potassium t-butoxide) [11, 95, 96]. However, it is clear that the addition of nucleophiles to such aromatic systems is a very unfavorable process, due to the... 

Nucleophilic Trapping of Radical Cations. To investigate some of the properties of Mh radical cations these intermediates have been generated in two one-electron oxidant systems. The first contains iodine as oxidant and pyridine as nucleophile and solvent (8-10), while the second contains Mn(0Ac) in acetic acid (10,11). Studies with a number of PAH indicate that the formation of pyridinium-PAH or acetoxy-PAH by one-electron oxidation with Mn(0Ac)3 or iodine, respectively, is related to the ionization potential (IP) of the PAH. For PAH with relatively high IP, such as phenanthrene, chrysene, 5-methyl chrysene and dibenz[a,h]anthracene, no reaction occurs with these two oxidant systems. Another important factor influencing the specific reactivity of PAH radical cations with nucleophiles is localization of the positive charge at one or a few carbon atoms in the radical cation. 

Examples of photosubstitution reactions of parent aromatic hydrocarbons are rare. Methylated anthracenes and dihydroanthracenes are, however, afforded by the irradiation of anthracene in the presence of methyl-lithium.98 The isomer distribution of methyl-anthracenes thus produced is very different from that observed from the thermal reaction, and the process appears to be only successful with higher methyl-lithium concentrations than were previously used.97 The reaction is also reported to occur with naphthalene and phenanthrene.98 The efficiency of light-induced substitution reactions of methoxyanthraquinones with nucleophiles has been shown to be very dependent upon the position of the methoxy-group and the particular nucleophile.98 In general, the 1-methoxy-derivative is more reactive than the 2-isomer, and whereas reaction was observed... 

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