Methyllithium: Lithium, methyl

Methyl chloroformate Formic acid, chloro-, methyl ester (8) Carbonochloridlc acid, methyl ester (9) (79-22-1) Methyllithium Lithium, methyl- (8,9) (917-54-4)... 

Methyllithium - lithium bromide complex Lithium, methyl- (8,9) (917-54-4)... 

This is a two-step transformation. The first step is an addition-ehmination reaction of methyllithium with methyl acetate transiently forming acetone. The second step is a 1,2-addition of methyllithium to acetone forming the final tert-butyl alcohol. Hydrochloric acid is present only to quench the formed anions and liberate a neutral product. The steps of this transformation are illustrated below using arrow pushing. Please note that, for simplicity, association of the lithium cations with the anions of the illustrated mechanistic pathway is not shown. 

The reaction of methyl trichloromethyl ether with methyllithium, lithium iodide and cyclo-pentadiene gives anisole. It is formed by the rearrangement of the chloro(methoxy)carbene (or carbenoid) adduct... 

METHYL-1.3-CYCLOPENTANEDIONE. 70, 226 Methylene transfer reagent, 70,187 Methyllithium-lithium bromide complex, 70,165... 

Lithium methyl mercaptide, CHsSLi. Mol. wt. 54.04, stable off-white solid. The material is prepared by the reaction of methyllithium with methyl mercaptan in anhydrous ether at 0°(N2). A slurry of CHuSLi is formed, from which ether and... 

Although ethereal solutions of methyl lithium may be prepared by the reaction of lithium wire with either methyl iodide or methyl bromide in ether solution, the molar equivalent of lithium iodide or lithium bromide formed in these reactions remains in solution and forms, in part, a complex with the methyllithium. Certain of the ethereal solutions of methyl 1ithium currently marketed by several suppliers including Alfa Products, Morton/Thiokol, Inc., Aldrich Chemical Company, and Lithium Corporation of America, Inc., have been prepared from methyl bromide and contain a full molar equivalent of lithium bromide. In several applications such as the use of methyllithium to prepare lithium dimethyl cuprate or the use of methyllithium in 1,2-dimethyoxyethane to prepare lithium enolates from enol acetates or triraethyl silyl enol ethers, the presence of this lithium salt interferes with the titration and use of methyllithium. There is also evidence which indicates that the stereochemistry observed during addition of methyllithium to carbonyl compounds may be influenced significantly by the presence of a lithium salt in the reaction solution. For these reasons it is often desirable to have ethereal solutions... 

The reaction of lithium with methyl chloride in ether solution produces a solution of methyllithium from which most of the relatively insoluble lithium chloride precipitates. Ethereal solutions of halide-free" methyllithium, containing 2-5 mole percent of lithium chloride, were formerly marketed by Foote Mineral Company and by Lithium Corporation of America, Inc., but this product has been discontinued by both companies. Comparable solutions are also marketed by Alfa Products and by Aldrich Chemical Company these solutions have a limited shelf-life and older solutions have often deteriorated... 

An ethereal solution approximately 2.5 molar in methyllithium is prepared from 17 ml of methyl iodide and 4 g of lithium metal in 200 ml of anhydrous ether. A mixture consisting of 150 ml anhydrous ether, 3 g (10 mmoles) of 3jS-hydroxy-5a-androstane-ll,17-dione and 60 ml (0.15 moles) of the above methyllithium solution are stirred at room temperature for 40 hr. The reaction mixture is diluted with 100 ml of water and the ether is removed by distillation. Filtration of the chilled aqueous phase yields 2.6 g (77%) of 1 la,17a-dimethyl-5a-androstane-3a,l l/ ,17j5-triol mp 149-154°. Recrystallization from acetone-hexane yields pure material mp 164-166° [a] —5° (CHCI3). 

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