Lithiation compounds

Scheme 9.1 describes reactions with several lithiated compounds, including dichloromethane, dichloromethyl methyl ether, phenylthiomethyl methyl ether, and phenylthioacetals. Compare the structure of these reagents and the final products for these reactions. Develop a mechanistic outline that encompasses these reactions. Discuss the features that these reagents have in common with one another and with carbon monoxide. 

Alkenylbenzotriazoles 865 are readily prepared by isomerization of the corresponding allyl derivatives catalyzed by Bu OK. Lithiated compounds 865 are treated with electrophiles to provide a-substituted derivatives 866. Epoxidation of the double bond with ///-chloroperbenzoic acid converts intermediates 866 into oxiranes 867 that can be hydrolyzed to furnish a-hydroxyketones 868 in good yields (Scheme 140) <1996SC2657>. 

There have been a number of studies of the physical and bonding behavior of these mixed transition-metal oxides, which conclude that in the fully lithiated compounds the cobalt is trivalent, the nickel predominantly divalent, and the manganese tetra-valent. Thus, the electrochemically active species is predominantly nickel with the cobalt playing an... 

At first the fact that the formation of the bicyclic compound P(SiMe2)3P could not be observed seemed incomprehensible. An explanation can be that this compound, under the given reaction conditions, reacts further to form compound 10. But compound 10 cannot be formed only in this way, as is demonstrated by the isolation of its precursor 9 and of the lithiated compound 11, which should react with Me2SiCl2 to form 10. Compound 10 is doubtlessly a favored molecule in the series of these cyclic silylphosphanes. 

Three different di- and trilithiated phenylmethanes 93, 95 and 97 were generated by Baran Jr. and Lagow. Dichlorodiphenyhnethane (92), dichlorophenyhnethane (94) and trichlorophenyhnethane (96) were reacted with the appropriate amount of f-butyllithium in THF at very low temperatures. Except for dihthiodiphenyhnethane (93), the observed yields were very low, verified by deuteriolysis of the lithiated compounds (Scheme 33). 

On the contrary, when bis(tributylstannomethyl)silane 100 is reacted with two eqniv-alents of w-butyllithinm in diethyl ether, only monohthiated compound 102 is formed . The donbly lithiated compound 101 is not accessible by this method (Scheme 35). 

Due to the formation of phenyUithium, the reaction of bis(phenyltelluriomethyl)silane 118 with w-butyllithium does not lead to the doubly lithiated compound 117a, but to the bis(butyltelluriomethyl)silane 119 and phenyUithium (Scheme 43) . 

The lithiated compound was obtained via the vinyltin derivative which was first converted into the vinyl iodide before doing the halogen-metal exchange, Fig. (30 and 31). 

Deprotonation of (alkylcyclopropylidenemethyl)cyclopropanes (alkyl = methyl, cyclopropyl) with BuLi and subsequent reactions with various electrophiles afforded the corresponding ring-substituted methylenecyclopropanes (equation 295)365. When the lithiated compounds are treated with C02, carboxylic acids are obtained, together with isomeric lactones. These can be regarded as formal 3+2 adducts of the methylenecyclopropanes with C02 (equation 295)366. 

EtsSiLi is formed along with EtLi, when the mercury compound EtHgSiEt3 is reacted with lithium in benzene (equation 10). However, when this reaction is performed in THF, EtsSiLi is obtained as sole lithiated compound (equation ll)17. 

An interesting Fe-catalyzed SN2 -like carbene insertion reaction using diazo compounds and allyl sulfides (the Doyle-Kirmse reaction) was reported by Carter and Van Vranken in 2000 [20], Various allyl thioethers were reacted with TMS-diazomethane in the presence of catalytic amounts of Fe(dppe)Cl2 to furnish the desired insertion products with moderate levels of stereocontrol [Equation (7.6), Scheme 7.14]. The products obtained serve as versatile synthons in organic chemistry, e.g. reductive desulfurization furnishes lithiated compounds that can be used in Peterson-type oleftnations to yield alkenes [Equation (7.7), Scheme 7.14] [21]. 

In using the halogenated organic group, an alternative is to form the lithiated compound, followed by silylation with chlorotrialkoxysilane. This was used in particular for the 1,1" terphenyl precursor 42, or the precursor with 9,10-anthryl group 43. The expected compounds are obtained in good yields (equation 6)92. 

The lithiated compound derived from 120 and also other cr-phenylselanylcyclohexyllithium compounds are configurationally labile even at low temperatures.203,204 The diastereoselection in the selenium-lithium exchange... 

Butyl 3-thienyl tellurium was lithiated exclusively in the 5-position of the thiophene ring upon treatment with lithium diisopropylamide. The lithiated compound reacted with dimethylacetamide to produce 5-acetyl-3-thienyl butyl tellurium1. 

The replacement of pure metallic Li by Li metal encapsulated in carbon as the anode led to a technologically important difference. While originally metallic lithium was the lithium source in the cell, it proved advantageous to use the positive electrode as the Li source. In other words, lithiated compounds were used as positive electrodes, and the cell was manufactured in the discharged state. 

The lithiation of 3a-3y with one equivalent RLi yields the lithiated compounds 4a, 4p, which differ in the configuration of the endocyclic phosphorus atoms. Both isomers were characterized by their P NMR spectra, which show characteristic AMX2 spin systems with shifts in the typical range of lithium silylphosphides(-160 to -210 ppm). 

When trimethylphenylhydrazine (1) is treated with nbutyllithium in the presence of tetramethyl-ethylenediamine, the orr/to-lithiated compound 2 is formed, which reacts with tetrachlorosilane or [2-(dimethylaminomethyl)phenyl]trichlorosilane to yield dichlorosilanes 3 and 4, respectively (Scheme 1). Both compoimds can be transformed into the corresponding silanes and diethoxysilanes. 

The a-chloro-a-sultinyl ketone 20 was prepared from methyl benzoate and chloromethyl phenyl sulfoxide 19 after in situ a-lithiation. Compound 20 is dimetallated by KH and f-BuLi to give the keto dianion 21, which is converted into a potassium/lithium ynolate 22 (equation 7). The resulting metal ynolates are converted into thioesters, carboxylic acids, amides and esters (Section V). 

Quite a number of nuclei can be used as reporters or spies in structural NMR research in the field of lithiated compounds, among them those of highest... 

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