Magnesium, alkyl-alkoxides

Two magnesium-rich species, which adopt cubane-type motifs, have recently been isolated. The first is the tetranuclear hthium-trimagnesium alkyl alkoxide [(THF)LiMg3Me3(OC6Hu)4] 24 (Fig. 17). The metal cations and alkoxide anions occupy the comers of the cube, and the methyl hgands are terminally bound to the Mg centers. The coordination sphere... 

BaiUie SE, Blair VL, HeviaE, Kennedy AR. A new polymeric alkyl/alkoxide magnesium-sodium inverse crown complex. Acta Crystallogr C. 2011 67(7) m249-m251. 

The preparations involve a magnesium alkyl (MgR MgR /AlR or RMgX) and a titanium-chloride compoxmd as the source of Ti, but mixtures of a titanium chloride compound and a titanium alkoxide compound have also been used. 

Dialkylaminoethyl acryhc esters are readily prepared by transesterification of the corresponding dialkylaminoethanol (102,103). Catalysts include strong acids and tetraalkyl titanates for higher alkyl esters and titanates, sodium phenoxides, magnesium alkoxides, and dialkyitin oxides, as well as titanium and zirconium chelates, for the preparation of functional esters. Because of loss of catalyst activity during the reaction, incremental or continuous additions may be required to maintain an adequate reaction rate. 

A related class of compounds are the alkyl-magnesium alkoxides these can be prepared by reaction of MgR2 with an alcohol or ketone or by reaction of Mg metal with the appropriate alcohol and alkyl chloride in methylcyclohexane solvent, e.g. ... 

Nucleophilic addition of an alkyl group R- to the aldehyde or ketone produces a teliahedral magnesium alkoxide intermediate. . . ... 

Alkali metal alkyls, particularly n-butyl lithium, are the most frequently used reagents to form metallated intermediates.246 247 In certain cases (di- and triphenyl-methane, acetylene and 1-alkynes, cyclopentadiene) alkali metals can be directly applied. Grignard reagents are used to form magnesium acetylides and cyclopenta-dienyl complexes.248 Organolithium compounds with a bulky alkoxide, most notably M-BuLi-ferf-BuOK in THF/hexane mixture, known as the Lochmann-Schlosser reagent or LICKOR superbase, are more active and versatile reagents.249-252... 

A convenient alternative procedure for alkylmagnesium alkoxides, which avoids the sometimes tedious preparation of a dialkylmagnesium compound, is the reaction of an alkyl chloride, magnesium and an alcohol, in a medium (such as a hydrocarbon) in which magnesium chloride is insoluble [28],... 

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