Organolithium compounds complexes

Chromium carbene complexes like 13, which are called Fischer carbene complexes, can conveniently be prepared from chromium hexacarbonyl 11 and an organolithium compound 12, followed by an O-alkylation step ... 

J-Oxygen-functionalised sp3 organolithium compounds react with alkenyl-carbene complexes to generate the corresponding cyclic carbene complexes in a formal [3+3] process (see Sect. 2.8.1). In those cases where the organolithium derivative contains a double bond in an appropriate position, tricyclic ether derivatives are the only products isolated. These compounds derive from an intramolecular cyclopropanation of the corresponding cyclic carbene complex intermediate [89] (Scheme 83). 

Ge—metal bonds can be built in analogy as described for Ge—C bonds by the reaction of organolithium compounds with metal halides. With trans-dichlorobis(triethylphosphine)platinum(II), new germyl transition metal complexes were synthesized (equation 36)41. 

Related to these catalysts are the systems based on lanthanide metal systems or rare earth metal complexes [46, 47]. The main problem with these catalyst systems is their instability. When the catalyst solution is prepared by reachng a metallocene with an organolithium compound in a polar solvent, the prepared catalyst soluhon is unstable and decomposes quickly, even under a nitrogen atmosphere. The activity of these catalysts can be high only if the catalyst is added to the polymer soluhon immediately after preparation. Attempts have been made to overcome the stability problem by using an additive in the system to improve the stability and the activity of the catalyst [33-35, 41, 57, 58, 61]. Re-... 

Lithium cobalt dioxide, uses, 7 24 It Lithium complex greases, 15 243 Lithium compounds, 20 598-599. See also Organolithium compounds inorganic, 15 136-142 uses for, 15 134 Lithium cyanide, 8 194 Lithium 5—alumina, 2 406t... 

The use of sterically hindered secondary organolithium reagents, such as (CgH jCH Li, drastically favors the O-alkyl scission of thejbster group (37) finally, organolithium compounds leading to non enolizable keto functions in the first step of substitution, such as C H Li, promote competitive and consecutive reactions resulting in complex copolymers of poorly defined structure (38,39) ... 

Elimination to yield alkenes can be induced thermally or by treatment with acids or bases (for one possible mechanism, see Figure 3.39) [138,206]. Less common thermal demetallations include the thermolysis of arylmethyloxy(phenyl)carbene complexes, which can lead to the formation of aryl-substituted acetophenones [276]. Further, (difluoroboroxy)carbene complexes of molybdenum, which can be prepared by treating molybdenum hexacarbonyl with an organolithium compound and then with boron trifluoride etherate at -60 °C, decompose at room temperature to yield acyl radicals [277]. 

A further synthetic approach to carbon-metal double bonds is based on the acid-catalyzed abstraction of alkoxy groups from a-alkoxyalkyl complexes [436 -439] (Figure 3.11). These carbene complex precursors can be prepared from alk-oxycarbene complexes (Fischer-type carbene complexes) either by reduction with borohydrides or alanates [23,55,63,104,439-445] or by addition of organolithium compounds (nucleophilic addition to the carbene carbon atom) [391,446-452]. 

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