Organoalkalis

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. 

A. A. Morton, Solid Organoalkali Metal Reagents, Gordon Breach, New York, 1964. 

Base catalysis is most effective with alkali metals dispersed on solid supports or, in the homogeneous form, as aldoxides, amides, and so on. Small amounts of promoters form organoalkali comnpounds that really contribute the catalytic power. Basic ion exchange resins also are usebil. Base-catalyzed processes include isomerization and oligomerization of olefins, reactions of olefins with aromatics, and hydrogenation of polynuclear aromatics. 

Typical initiators for living anionic polymerization of siloxanes include conventional organoalkali compounds and lithium siloxanolates22). Initiators containing lithium counterions are preferable to sodium or potassium counterions due to the lower catalytic activity of lithium in siloxane redistribution reactions. Living anionic polymeriza-... 

In addition to the decreased polarizability of the heavier metals, their larger radii require higher metal coordination numbers to achieve steric saturation. As a result, extensive aggregation, frequently coinciding with rather limited solubility in non-donor solvents, and occasionally even in donor solvents, complicates the characterization of these species in solution and the solid state. In fact, several structural characterizations of organoalkali species have relied on recent advances in powder diffraction techniques using synchrotron radiation.1 ... 

The strong tendency toward aggregation, a commonly observed structural motif within organoalkali metal derivatives, is widely observed in alkali metal alkynyl chemistry, likely due to the small size of the ligand. 

Schlosser, M. Organoalkali Chemistry. In Organometallics in Synthesis - A Manual, Schlosser, M., Ed. Wiley Ghicester, 2002 Chapter 1. 

Kinetics in Polar Media. These polymerizations, initiated by organoalkali compounds mainly in ether solvents, have... 

Bywater and coworkers (5,6) employed 1JC nmr to identify the the shift positions and to estimate the charge distribution over the various carbon positions in several organoalkali metal model compounds of butadiene and isoprene. They concluded that all of the compounds are delocalized ionic compounds in the solvents, and several ethers. 

The nature of the catalyst and certain experimental observations, such as product distribution [Eq. (5.61)], indicate a carbanionic reaction mechanism. A benzylic carbanion formed through proton abstraction by an organoalkali metal compound... 

All unsaturated hydrocarbons that possess removable allylic hydrogens or activated double bonds readily undergo oligomerization in the presence of basic reagents.30,31 Alkali metals, organoalkali compounds, and alkali alcoholates are most frequently applied. 

Organoalkali metal compounds may also be obtained from reactions between organomercury compounds and the elemental metals. 

This represented the discovery of the first addition of an organometallic (organoalkali) compound to a C=C double bond. The organopotassium compound used had at that time been known for only 4 years. It was found by the author and Schnell (46) as the result of a systematic search for the simplest ether to be split by an alkali metal according to the equation... 

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 ... 

Dover BT, Kamienski CW, Morrison RC, Currin RT, Schwindeman JA. Organoalkali compounds and their preparation. US Patent, 5976403, 1999. 

T. Cohen, M. Bhupathy, Organoalkali Compounds by Radical Anion Induced Reductive Metalation of Phenyl Thioethers, Acc. Chem. Res. 1989, 22, 152-161. 

Most of the progress concerning organoalkali reagents in chemistry have been made using superbases. The following sections deal with the preparation and use of organoalkali compounds of vinyl, aryl, and benzyl type. 

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 ... 

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