Lithium naphthalene metallating agent

This approach frequently leads to the most active metals as the relatively short reduction times at low temperatures leads to reduced sintering of the metal particles and hence higher reactivity. Fujita, et aL(62) have recently shown that lithium naphthalide in tqluepe can be prepared by sonicating lithium, naphthalene, and N, N, N, N-tetramethylethylene-diamine (TMEDA) in toluene. This allows reductions of metal salts in hydrocarbon solvents. This proved to be especially beneficial with cadmium(49). An extension of this approach is to use the solid dilithium salt of the dianion of naphthalene. Use of this reducing agent in a hydrocarbon solvent is essential in the preparation of highly reactive uranium(54). This will be discussed in detail below. 

Acetylenic diols. Ref. 4, 2, 289 Definitive paper, S. Watanabe, K. Suga, and T. Suzuki, Canad. J. Chem., 47, 2343 (1969). Naphthalene-lithium was found to be superior to other metalating agents (naphthalene-sodium, n-butylmagnesium bromide) in this synthesis. 

A far superior method of preparing the highly reactive zinc is to use lithium metal as the reducing agent along with an electron carrier such as naphthalene (Method 2). This approach is considerably safer as there is no rapid burst of heat. The dark green lithium naphthalenide also serves as an indicator, signaling when the reduction is over. 

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