Organometallic compound polarity

SCHEME 22. Stereochemical outcome of the addition of polar organometallic compounds R"M to a-alkoxy aldehydes and ketones (G = protecting group)... 

C. Lambert and P. v. R. Schleyer, Angew. Chem., 106,1187 (1994) Angew. Chetn. lnt. Ed. Engl., 33, 1129 (1994). Are Polar Organometallic Compounds Carbanions The Gege-nion Effect on Structure and Energies of Alkali-Metal Compounds. 

Hill, E. A. Richey, H. G. Rees, T. C. Intramolecular cleavages and double bond additions of polar organometallic compounds. J. Org. 

The reaction of a polar organometallic compound with elemental sulfur, selenium or tellurium gives a thiolate, selenolate or tellurolate, respectively [60, 61] in many syntheses, however, further reactions are carried out with the intermediary chalcogenates , e.g. alkylations ... 

Whereas iodinations of polar organometallic compounds in most cases are carried out with elemental iodine (see for example Exp. 40) the aggressive nature of chlorine may give rise to side and subsequent reactions, or reactions with the organic solvent. However, there are a number of compounds, containing so-called positive... 

Table 2. Alkylation of polar organometallic compounds with c-hexyl bromide...

Many sp- and sp2-polar organometallic compounds can be successfully converted into sp- and sp2-halogen derivatives by reaction with free halogen or a suitable halogenating agent ... 

The term polar organometallic compounds refers generally to compounds of carbon with electropositive elements, most commonly the compounds of the alkali and alkaline earth elements. In these compounds, the electronegativity difference (see Electronegativity and the Periodic Table) between carbon and the metal indicates that the polar resonance structure IB contributes greatly to the resonance hybrid ... 

HMPA Substitutes and Analogs. Researchers have searched for an alternative to HMPA. Such a solvent must be stable to polar organometallic compounds and be comparable to HMPA in its many functions. Replacement solvents typically are useful in some applications but have limited value in others. Examples of some useful alternatives are (15)-(19). ... 

Lambert C, PvR S (1994) Are polar organometallic compounds carbanions The gegenion effect on structure and energies of alkali-metal compounds. Angew Chem Int Ed Engl 33 1129-1140... 

---