Organohthium compounds

These compounds are soluble in ether, are comparatively stable, and exhibit many of the reactions of Grignard reagents but are more reactive. Because of their greater reactivity, organohthium compounds can often be used where Grignard reagents fail thus they add to the azomethine linkage in pyridines or... 

The silylated compound can be reacted further with other organohthium compounds to give substituted silylated difluorovinyl compounds (equation 34)... 

The mechanism of the reaction between a hydrocarbon organohthium compound and a carbonyl compound is well-documented [69] and has been suggested earlier for fluonne-contaming compounds [32, 68, 70] More recent studies on the mechanism have resulted in a better understanding of this reaction [71] (equauon 37)... 

Wakefield, B J Organohthium Compounds, Pergamon Press New York, 1976, p 136... 

TABLE lb. Li chemical shifts, in ppm", of selected organohthium compounds in various solvents ... 

Metallation of variously substimted benzanilides (389), followed by treatment with an electrophile, lead to the formation of 2-aryl-3-hydroxyisoindol-l-ones (391), as shown in equation 105. The intermediate organohthium compound (390) closes a five-membered... 

The chemistry of lithium carbenoids, organohthium compounds with an electronegative heteroatom in the a-position, has been developed in two respects during the last two decades. First, the ambiphilic character of these partly short-lived and mostly thermally sensitive compounds is well understood today, due to structure determinations, spectroscopic investigations and theoretical calculations. Second, many of the lithium carbenoids, formerly considered as exotic species, have developed into useful reagents that proved to be particularly fruitful in stereoselective syntheses. 

The chemistry of organohthium compounds / edited by Zvi Rappoport, Ilan Marek. p. cm.—(Chemistry of functional groups)... 

Organohthium compounds. I. Rappoport, Zvi. II. Marek, Ilan. III. Series. 

Initiators -for acrylamide [ACRYLAMIDE POLYMERS] (Vol 1) -anionic initiators [INITIATORS - ANIONIC INITIATORS] (Voll4) -cationic initiators [INITIATORS - CATIONIC INITIATORS] (Vol 14) -in emulsion polymerization [LATEX TECHNOLOGY] (Vol 15) -for fluorocarbon elastomers [ELASTOMERS, SYNTHETIC - FLUOROCARBON ELASTOMERS] (Vol 8) -Free-radical initiators [INITIATORS - FREE-RADICAL INITIATORS] (Voll4) -organohthium compounds as [LITHIUM AND LITHIUM COMPOUNDS] (Vol 15) -peroxides as [PEROXIDES AND PEROXIDE COMPOUNDS - INORGANIC PEROXIDES] (Vol 18) -for propylene oxide [PROPYLENE OXIDE] (Vol 20) -for PUR polyols [POLYETHERS - PROPYLENE OXIDE POLYMERS] (Vol 19) -of suspension polymerization [ACRYLIC ESTER POLYMERS - SURVEY] (Vol 1)... 

However, l,2-difluoro-l-chloro-2-ethoxyethylene yields two organohthium compounds (equation 29). 

With a difluoroethylene containing hydrogen and chlonne, where both groups can be replaced by lithium, a mixture of two organohthium compounds is formed in a 2 1 ratio, indicating a more facile replacement of chlonne [63] (equation 30)... 

The last electrophilic substitution reaction of a Grignard compound we want to consider is a transmetallation, namely one that leads to an arylboronic ester (Figure 5.38). Arylboronic esters or their hydrolysis products, the arylboronic acids, are valuable reagents in modem aromatic chemistry. They react with a series of electrophiles that would not react with Grignard or organohthium compounds (Sections 5.3.3 and 13.3.2). 

From the viewpoint of polar, yet covalent Li—O and Li—N bonds, hthium would be unable to reach a valence electron octet in the absence of bonding partners in addition to the heteroatom. The hthium thus has to surround itself by other donors in much the same way as has been seen in the case of the organohthium compounds (cf. Section 8.1). 

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