ChemInform Abstract: LOESUNGEN CALCIUMORGANISCHER VERBINDUNGEN VOM TYP AR2CA

Abstract

Amalgamiertes Calcium verdrängt das Quecksilber aus den quecksilberorganisehen Verbindungen (I), wobei Lösungen der calciumorganischen Verbindungen (II) entstehen.

Reactivity studies of phenylcalcium iodide towards THF yielding phenyl-free cage compounds – Crystal structures of [{(thf)Ca(O–CHCH2)2}4·CaO·CaI2] and [(CaO)4·4 (thf)3CaI2]

“…It was also observed in the NMR spectrum that the concentration of phenyl groups decreased and that the amount of benzene increased. After complete conversion of the phenyl groups into benzene via ether cleavage we were able to isolate a phenyl-free octa-nuclear cage compound of the type [(CaO) 4 …”

“…In the beginning of the research on organocalcium halides, RH was often identified after protolysis of RCaX with water or acids in order to determine the yields [4,18,19]. Due to ether cleavage reactions, the amount of RH was enhanced as a consequence of a-deprotonation reactions of RCaX with the solvent THF.…”

“…On the one hand, the preparation of PhCaI was performed in hot Et 2 O [4], treatment of its 1,4-dioxane adduct at 110°C led to loss of coordinated ether and to formation of high-melting PhCaI [5,6]. The synthesis of diphenylcalcium was performed in boiling ether from Ca and HgPh 2 within 25 h [7], higher yields up to 92% were achieved in THF solution [7,8]. Thereafter, CaPh 2 was used to deprotonate fluorene, triphenyl-and diphenylmethane [9].…”

Reinvestigation of the synthesis of phenylcalcium iodide and the first structural characterization of a heavy Grignard reagent as [((thf)2CaPhI)3·(thf)CaO] with a central Ca4 tetrahedron

“…Phenylcalcium halides are reported for all halides and several preparation procedures have been developed [2]. The reactions of halogenobenzene with calcium vapor (co-condensation reaction) [3] as well as with calcium in a solvent (direct synthesis) [4] are the main access routes. Calcium-tellurium exchange reactions (transmetallation) have also been considered [5].…”

Synthesis of 2,4,6‐Trimethylphenylcalcium Iodide and Degradation in THF Solution

“…In order to overcome these problems several preparative procedures have been developed. [1,2] The main access routes to organocalcium compounds are: 1) the reaction of halogenated hydrocarbons with calcium vapor (cocondensation reaction), [3,4] 2) the insertion of calcium into a carbon-halogen bond in solution (direct synthesis), [5] 3) the substitution of a less electropositive metal by calcium (transmetalation), [6,7] 4) the deprotonation of H-acidic hydrocarbons by calcium or calcium compounds (metalation), [8] 5) the reaction of a organopotassium compound with anhydrous CaI 2 (metathesis reaction). [9,10] Beckmann described the synthesis of phenylcalcium iodide in 1905; he applied the direct synthesis in diethyl ether and activated the alkaline-earth metal with a trace of iodine.…”