Alkylsodium compounds

These catalysts require temperatures above 100° and usually 150-200° for reasonable rates. Alkylsodium compounds at their decomposition temperatures (50-90°) have also been used by Pines and Haag (9). Lithium reacted with ethylene diamine has also been reported by Reggel et al. (4) as a catalyst for this reaction. The homogeneous system thus formed seems to lower the temperature requirement to 100° (4), whereas the use of potassium amide in liquid ammonia requires 120° (S). Sodium reacted with ethylene diamine has been reported to be an ineffective catalyst (4)- The most active catalyst systems reported so far are high-surface alkali metals and activated-alumina supports. They are very effective at or near room temperature (10-12). 

The same difficulty also occurs in the preparation of alkylsodium compounds. The starting halide RX couples with RNa (to give R—R and NaX) or is converted to an alkene. These reactions appear to involve radical intermediates undergoing combination and disproportionation (Section 10-8C) ... 

The Vuitz or Wnrtz-Fittig synthesis is usually thought of as a coupling reaction of two molecules of a halide or different halides by metallic sodium. In the liquid phase, as the reaction is generally carried out, alkylsodium compounds are intermediates and the coupling stage or second step is comparable to the reactions discussed above. °... 

Q Although alkylsodium compounds react with diethyl eiher, orga nomagnesium halides (Grignard reagents) do not. Why is this ... 

The accompanying papers in this volume, the literature cited in them, and this paper discuss reasons for the enhanced reactivity of these complexes. Mechanistic discussion has been left to a minimum in this paper to emphasize preparative and synthetic aspects. (A useful analogy as to what these complexes can do or how they will react is to consider their behavior to be similar to hydrocarbon soluble alkylsodium compounds if they were to exist.)... 

The Wurtz reaction constitutes the direct coupling of the nucleophilic carbon of an alkylsodium compound and the electrophilic carbon in a haloalkane. It is an unselective reaction. There is no way to control it to prevent coupling of two like alkyl groups while attempting to couple two different ones. In other words, the reaction between chloroethane and 1-chloropropane gives a statistical mixture of butane (from two ethyls), pentane (from an ethyl and a propyl), and hexane (from two propyls). 

Alkylsodium and alkylpotassium compounds are highly reactive and are among the most powerful of bases => they react explosively with water and burst into flame when exposed to air. 

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