Carbonates, arene-catalyzed lithiation

Although the most important reaction of rednctive carbon-snlfnr bond cleavage involves alkyl phenyl thioethers, arene-catalyzed lithiation has also been studied using other snlfnr-containing componnds, snch as thiols, disnlhdes, snlfoxides and sulfones. 

Dioxanes can be opened by an arene-catalyzed lithiation only if the carbon-oxygen bond to be cleaved occupies an allylic or benzylic position. This is the case of the vinyl-dioxane 416, which reacted with lithium and a catalytic amount of DTBB in THE at 0 °C, and the allylic intermediate 417 generated reacted at the y -position with tridecyl iodide to yield the compound 418, used in the synthesis of plasmenyl-type lipids (Scheme 117) . 

The different reactivity of both carbon-chlorine and carbon-oxygen bonds toward arene-catalyzed lithiation (see Scheme 129) was applied to 3-chloropropyl phenyl ether... 

Not included in the former sections are methodologies involving arene-catalyzed lithiation that are based on deprotonation reactions, carbon-carbon bond cleavage, addition processes as well as the preparation of lithium telluride. 

Cyclic alkyl aryl ethers lead also to functionalized organolithium compounds by reductive carbon-oxygen bond cleavage in arene-catalyzed lithiation process. Thus, the treatment of 2,3-dihydrobenzofuran (47) with an excess of lithium in the presence of a catalytic amount of DTBB in THF at 0°C gives the dianion (48) which after reaction with different carbonyl compounds and final hydrolysis with water leads to... 

As expected, only few examples involving carbon-carbon bond cleavage have been described in the literature. Namely, only nitriles and A-methoxycarboxamides undergo a reductive carbon-carbon bond cleavage by lithiation under arene-catalyzed conditions. 

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