Organolithium compounds oxidation

We have previously reported the results of careful investigations of the solution carbonation (8) and oxidation (9) of polymeric organolithium compounds. These studies have been extended to the investigation of solid-state carbonation reactions and these results are reported herein. In addition, a new method has been developed for the synthesis of telechelic polymers with primary amine end-group... 

Adogen 464, coupling reagent, poly(phenylene oxide), 190 Amination, polymeric organolithium compounds, 139-145... 

THF is used as solvent for this reaction (Scheme 156). Indeed, THF is the solvent of choice for the alkylation of N- oxides by Grignard reagents. The following references (B-71MI20500, 74HC(14-S2)i) should be consulted for a more comprehensive coverage of these reactions. Reactions of the above type with organolithium compounds are less successful as metallation becomes a major pathway (vide infra). 

The key step is the addition of a large excess of the organolithium compound to carboxylic acid 2 to form ketone 3. This in turn is reduced via the thioketal to form 4 which is oxidized at the former alcohol position to give, after N deprotection, the desired amino acid 5. 

Organometallic compounds which contain a carbon-metal bond are the most reactive carbon nucleophiles. In most cases they are also powerful bases and must be prepared and used under strictly anhydrous and aprotic conditions. A very common way to produce organometallic compounds is to reduce alkyl halides with active metals. Grignard reagents and organolithium compounds are routinely produced in this manner. The transformation is a two-electron reduction of the alkyl halide to a carbanion equivalent the metal is oxidized. 

With this background, the following range of products could be forme in the oxidation of a polymeric organolithium compound (Eq. (89)) as illustrated for polystyrene. q... 

Any rigorous study of the oxidation of polymeric organolithium compounds should consider these products and their variation in yield with reaction conditions. To date, few of these reaction products have been considered, let alone identified and analyzed. However, the presence of the macroperoxide has been identified recently among the products of the oxidation of poly(styryl)lithium 352). Lithium aluminium hydride reduction followed by SEC analysis of the dimer fraction before and after reduction... 

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