Lithium compounds levels

The corrosion resistance of lithium electrodes in contact with aprotic organic solvents is due to a particular protective film forming on the electrode surface when it first comes in contact witfi tfie solvent, preventing further interaction of the metal with the solvent. This film thus leads to a certain passivation of lithium, which, however, has the special feature of being efiective only while no current passes through the external circuit. The passive film does not prevent any of the current flow associated with the basic current-generating electrode reaction. The film contains insoluble lithium compounds (oxide, chloride) and products of solvent degradation. Its detailed chemical composition and physicochemical properties depend on the composition of the electrolyte solution and on the various impurity levels in this solution. 

In the mid- 1900s, doctors conducted experiments with patients suffering from depression, treating them with various lithium compounds. By the 1970s, lithium was commonly used in Europe and the United States to treat patients with manic depression, which is characterized by extreme mood swings. It is not clear exactly how lithium works to help patients. Some researchers believe that manic depression involves the overproduction of a chemical in the brain called inositol phosphate, and that lithium works to normalize levels of this chemical. 

Rychnovsky et al. initially prepared 4-Uthio-l,3-dioxanes by reductive lithiation of the 4-phenylthio derivatives 57 [Eq. (20)] [43,44]. The stereochemical features resemble those of the 2-lithiotetrahydropyrans (vide supra). Again, the axial lithium compound ax-58 is formed imder kinetic conditions, but the equatorial diastereomer eq-58 is favored by >4 kcal-mol this has been verified by quantum-chemical calculations at a high level [44]. Organocuprates derived from reagents such as ax-58 behave well [44]. 

While there is ample room for debate at the theoretical level, the importance of this straightforward route to compound 20 could hardly be missed. Attention could now be directed to the necessary functional group adjustments. Reduction of the ester (lithium triethoxyborohydride) followed by benzoylation (benzoyl chloride, DMAP) afforded an 80% yield of 22. Treatment of this compound with ruthenium dioxide in the presence of sodium metaperiodate, followed by diazomethane, provided ester 23 in 90% yield. 

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