Organoalkalis formation

Acetylenic Grignard compounds or the corresponding organoalkali metal derivatives are important intermediates in many syntheses of acetylenic compounds. The various methods for their formation in organic solvents and in liquid ammonia have been discussed extensively and we here give only a brief summary. 

The Si—H bond as well as the Si-halogen bond reacts with organoalkali compounds and this fact can be used formation of new derivatives ... 

Conductivity studies show that organoalkali compounds, such as ethyllithium, C2H5—Li, are good conductors when dissolved in diethyl-zinc. Ionization apparently occurs, and, since the formation of ethide ions, C2H7, is unlikely, the reaction may be best represented as a sbl-volysis by the acidic zinc compound ... 

The dimerization of propene at about 210° in the presence of potassium or cesium yielded 4-methyl-l-pentene as the predominant dimer (8). The dimerization proceeds through an initial formation of an organoalkali compound, followed by metalation of the propene. 

The formation of the metal hahde as a by-product limits the use of this method for the synthesis of reagents intended for further reactions. The relative solubihties of the organoalkali metal compounds and the metal hahdes formed in these reactions do not generally allow for easy separations. 

The reaction of conjugated dienes with Rj Al in THF in the presence of alkali metals provides more examples for complex formation between organoalkali and R3AI. There are differences for various dienes or olefins. With butadiene, Li or Na, McjAl the result is reminiscent of reactions (k) and (1) ... 

Functional End-Group Polymers. The formation of various functional groups on the "living" ends of anionic polymer chains is based on the well-known reaction of organometallic compounds with various reagents. Thus, organoalkali compounds can react as illustrated in the following typical reactions ... 

A synthetically useful reaction is the formation of sulfides from organoalkali compounds and disulfides ... 

Scheme 6.1 Formation of organoalkalis (X= H, Na, K) by engineering the carboxylate ligand to be a dianion (see Ref. [69]).

---