Lithium anilide

C. Reactions of Phosphoric and Phosphinic Acid Derivatives.—The optically active phosphinate ester (90) has been shown to react with benzyl Grignard reagents or lithium anilide with inversion of configuration. Oxidation of... 

It is intriguing to note that this reaction scheme for the reduction of a sulphone to a sulphide leads to the same reaction stoichiometry as proposed originally by Bordwell in 1951. Which of the three reaction pathways predominates will depend on the relative activation barriers for each process in any given molecule. All are known. Process (1) is preferred in somewhat strained cyclic sulphones (equations 22 and 24), process (2) occurs in the strained naphtho[l, 8-hc]thiete 1,1-dioxide, 2, cleavage of which leads to a reasonably stabilized aryl carbanion (equation 29) and process (3) occurs in unstrained sulphones, as outlined in equations (26) to (28). Examples of other nucleophiles attacking strained sulphones are in fact known. For instance, the very strained sulphone, 2, is cleaved by hydride from LAH, by methyllithium in ether at 20°, by sodium hydroxide in refluxing aqueous dioxane, and by lithium anilide in ether/THF at room temperature. In each case, the product resulted from a nucleophilic attack at the sulphonyl sulphur atom. Other examples of this process include the attack of hydroxide ion on highly strained thiirene S, S-dioxides , and an attack on norbornadienyl sulphone by methyllithium in ice-cold THF . ... 

Other changes in deprotonation conditions can influence enolate composition. Relatively weakly basic lithium anilides, specifically lithium 2,4,6-trichloroanilide and lithium diphenylamide, give high Z E ratios.10 Lithio l,l,3,3-tetramethyl-l,3-diphenyldisilylamide is also reported to favor the Z-enolate.11 On the other hand, lithium IV-trimethylsilyl-wo-propylamide and lithium iV-trimethylsilyl-fert-butylamide give selectivity for the fi-enolate12 (see Scheme 1.1). 

A range of rhodium complexes have been studied as hydroamination catalysts. Treatment of norbornene with a mixture of aniline and lithium anilide in the presence of [Rh(PEt3)2Cl]2 at 70 °C for over 1 week yields the exo addition product in ca. 15% yield.165... 

Scheme 2 Aggregated forms of variously solvated lithium anilides.

The family of complexes which contain amide/alkoxide functionalities constitute the largest group. The reaction of lithium anilide with TuONa, cBuOK, and TMEDA in a 2 1 1 2 ratio produced the remarkable trimetallic complex... 

Lithium anilide reacts with phenyl- or methyltin trichloride to give polynuclear Sn-N compounds, in which the phenyltin derivatives are four-coordinate and bicyclic (Equation (168)), and the methyltin derivatives are five-coordinate and tetracyclic.504... 

Treatment of 1,4-dimethylpiperazine (dmp) with lithium anilide LiNHPh gave [(LiNHPh)5(dmp)2]. " It has a distorted ladder structure with five Li—N rings. However, it is U-shaped rather than stepped as shown by 4 [N = NHPh N(dmp) = 1,4-dimethylpi-peridine] from which it can be seen that the bridgehead lithium is bound to... 

The triheterometaUic compound [ (PhHN)2(Bu O)LiNaK(tmeda)2 2], containing a 12-vertex Li2Na2K2N/ O2 cage structure (Figure 2.7), was synthesized in 78 % yield from lithium anilide, NaOBu, KOBu and tmeda in hexane under ultrasonication. " ... 

An enantioselective version of this allylamine synthesis employs the chiral (S,S)-dimethylzirconium derivative 3, prepared from (S,S)-[l,2-ethylenebis(tetrahydro-l-indenyl]zirconium dichloride.3 Displacement of one methyl group by triflic acid followed by reaction with a lithium anilide results in a zirconaaziridine (a) with loss of methane. Reaction of a with a symmetrical alkyne provides a metallapyrroline (b), which is hydrolyzed to an (S)-allylamine (4) in 90-99% ee. The method tolerates variation in the lithium anilide. Terminal alkynes do not react with a, but 1-trimeth-... 

Fig. 5.63. Synthesis of diphenylamine via an intermediate benzyne. The phenyl-lithium that has been formed in situ serves to generate lithium anilide. In the synthesis presented here lithium anilide plays the same role as sodium hydroxide in the reaction given in Figure 5.61 and potassium-tert-butoxide in the reaction shown in Figure 5.62.

The first equivalent of phenyllithium and aniline yield 1 equivalent of lithium anilide. 

The lithium anilide reacts with a third equivalents of bromobenzene to give 1 equivalent of benzyne. Simultaneously, 1 equivalent of aniline is regenerated. 

Refluxing 2,4-diphenyl-2H-thiete 1,1-dioxide in ethanol yields the acyclic sulfone 286. Treatment of naphthothiete sulfone 205b with methyllithium, sodium hydroxide, or lithium anilide gives products, for example, 287, resulting from nucleophilic attack on the sulfur atom of the sulfone... 

Diphenyl-2-methyl-1,2-dihydroquinolines (56) have been prepared from lithium anilides and phenylacetylene (Scheme 36). ... 

The key step in a new acridone (123) synthesis involves the oxidative coupling of the anilidocuprate generated from lithium anilide and copper(I)cyanide with the lithio derivative of a tertiary benzamide (121). The anthranilamide (122) formed is subsequently cyclised by treatment with heptafluorobutyric acid. 

Stevens and coworkers reported on the quasi-Favorskii rearrangement of a norborane derivative. The exo-2-bromo-e /o-2-benzoyl norborane 52 tmdergoes a rearrangement with lithium anilide as the nucleophile to form 53. The concerted semi-benzylic mechanism of this reaction produces only one of the possible isomeric products. A trace amount of the bromo-displaced product 54 was also observed. The rearranged product was... 

A number of substituted styrenes of the type C F3CR CR R e.g. CaFe CH CHEt, C,F5-CH CMe2) have been synthesized by dehydration with phosphorus pentoxide of alcohols [CeFj CRXOHj-CHR R ] obtained by the action of pentafluorophenylmagnesium chloride on appropriate carbonyl compounds. The kinetics of the thermal and AZBN-initiated polymerization of 2,3,4,5,6-pentafluorostyrene have been studied, and nucleophilic attack on this monomer by sodium methoxide, methylamine, dimethylamine, and lithium anilide has been shown to cause preferential displacement of the fluorine para to the vinyl group. ... 

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