Lithium compounds benzoate

Phenyl lithium attack on the cyclic carbonate convertes 202 to C-2 benzoate compound 203. PCC oxidation and subsequent NaBH4 reduction then furnishes the final baccatin III for the total synthesis of taxol (Scheme 7-65). 

In order to understand the formation of compounds now being discussed one has to realize that tris(trimethylsilyl)phosphane originating in the desilylation of [l-(trimethylsiloxy)benzylidene]-trimethylsilylphosphane (Scheme 1) reacts slowly with lithium ethanolate to give lithium bis(trimethylsilyl)phosphanide again (Eq. 13). This compound must then be considered a continuous source for the phosphaalkyne H5Q-C P, provided that a sufficient amoimt of ethyl benzoate is present in solution. 

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). 

Treatment of acetylmethylenetriphenylphosphorane with /i-butyllithium or lithium diisopropylamide results in abstraction of a methyl proton to form an yiide anion. Reactions of the 1,3-dicarbanion with electrophilic compounds including alkyl halides, aldehydes, ketones and benzoate esters occurs at the terminal carbanion site to afford a variety of substituted -ketophosphonium ylides (equation... 

The carbamate-stabilized allenyl anion was shown to have moderate configurational stability. Thus, when the 4-benzoate derivative of the allenyl compound is lithiated, 1,4-elimination of lithium benzoate. occurs to form the very reactive 3-alken-l-ynyl carbamates stereospecifically (Scheme 34). ... 

Synonims 1,2-cyclohexanedicarboxylic, acid calcium salt octacosanoic acid, calcium salt (2 1) calcium difluoride propanedioic acid, calcium salt (1 1) 1,5-pentane dicarboxylic acid, calcium salt (lR,2R,3S,4S)-rel-bicyclo[2.2.1]heptane-2,3-dicarboxylic acid, disodium salt mixture of polycarbonic acid salt and inorganic carbonate in a polymeric carrier, sodium 2,2 -methylene-bis-(4,6-di-tert-butylphenyl)phosphate bicyclic (2,2,1) heptane di-carboxylate 1,2-cyclohexanedicarboxylic acid, calcium salt -i- zinc stearate bicyclo[2.2.1]heptane-2,3-dicarbo lic acid, disodium salt, (IR, 2R, 3S, 4S)-rel-and a blend of amorphous silicon dioxide coated wilh 13-docosenamide in a 1 1 ratio proprietary zinc compound octacosanoic acid, calcium salt (2 1) benzoic acid, lithium salt zinc monoglycerolate sodium benzoate encapsulated sodium salts of carbonic and poly-carboxylic acids with styrene and SEES rubber carrier resins zinc,[l,2,3-propanetriolato(2-)-k01,k02]homopolymer, stereoisomer... 

Low-shrink polypropylene fibers requires presence of additive that nucleates polymer crystals within the target polypropylene after exposure to sufficient heat to melt the initial pelletized polymer and allowing such a melt to cool." The preferred rigidifying compounds include dibenzylidene sorbitol based compounds, as well as less preferred compounds, such as sodium benzoate, certain sodium and lithium phosphate salts (such as sodium 2,2 -methylene-bis-(4,6-di-tert-butylphenyl)phosphate, otherwise known as NA-11)."... 

When used in THF at room temperature, the base prepared from LiTMP and CoBr in a 3 1 ratio proves capable of deprotometalating different methoxybenzenes. The generated aryhnetal species can be trapped by different electrophiles iodine, anisaldehyde, and chlorodiphenylphosphine to respectively generate the corresponding iodide, alcohol, and phosphine in high yields and benzo-phenone, benzoyl chloride, and allyl bromide to afford the expected alcohol, ketone, and allylated compound in moderate yields (Table 27.10). The side formation of symmetrical dimers was observed in the course of these reactions, in particular using aUyl bromide such a side reaction (reduced by using the base in excess) could be initiated by one-electron transfer from a cobaltate species to the electrophile. This lithium-cobalt base is not suitable for the functionalization of sensitive substrates such as ethyl benzoate [109,110]. 

Full details have appeared of the a-oxo-lithiation of 2,6-disubstituted benzoate esters (6) having sterically protected carbonyl groups (c/. 3,133). Reaction of the lithio derivatives, formed from (6) by reaction with excess base or regenerated from the stannane (7) by treatment with stoicheiometric methyl-lithium, with alkyl halides or carbonyl compounds followed by ester cleavage leads to alcohols and diols, respectively (Scheme 9). 

Acetals and ketals of aromatic carbonyl compounds appear to be perfectly stable to the action of lithium aluminium hydride. Thus, the ester group of ethyl 4-acetyl benzoate can be reduced to the primary alcohol via its diethyl acetal [218]. 

Obtained at -78° in THF using lithium diisopropyl-amide (LDA), either by reaction between methyl 2-hydroxy-4,6-dimethoxy-3-(2-propenyl)-benzoate and (R)-(-i-)-methyl p-tolyl sulfoxide in the presence of l,3-dimethyl-3,4,5,6-tetrahydro-2[lW]-pyrimidinone (DMPU) (this method yields only a trace of the desired compound), or by reaction between 2-hydroxy-4,6-dimethoxy-3-(2-propenyl)benzaldehyde and (R)-(-b)-methyl p-tolyl sulfoxide via the subsequent oxidation % r.t. by MnO of the intermediate l-[2-hydroxy-4,6-dimethoxy-3-(2-propenyl)phenyl]-2-(4-methylsulfmyl)ethanol (57%) [5602]. 

The preparation of functionalized aryl boronic reagents can be achieved by directed metallation followed by a transmetallation of aryllithiums with organoboron compounds. Thus, Caron and Hawkins have described a directed ortho-metalla-tion of aryl neopentyl esters such as 1 for the synthesis of substituted ortho-horo-nyl neopentyl benzoates using lithium diisopropylamide (LDA) as the base and B(OiPr)3 as an in situ trap [3]. The crude boronic acids obtained by acidic hydrolysis were subsequently treated with ethanolamine and converted to stable diethanolamine complexes such as 2. This methodology allows the preparation of a new class of boronic acids with ortho-carbonyl substituents and other functionalities... 

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