Organomagnesiums, 154. esters

The first route is illustrated by the preparation of Ti " fixed on a polymer reduced by organomagnesium ester compounds which yields catalysts active in olefin isomerization and hydrogenation. Considerable differences between organomagnesium and organolithium compounds as reductants and between their respective... 

Magnesium methylate is used as a drying agent for alcohols and other organic solvents and as an intermediate in various manufacturing processes, eg, for organomagnesium compounds (79), orthocarbonic esters (80), and for oxide coatings. 

Magnesium ethylate is used as a drying agent for organic solvents, as an intermediate for the manufacture of organomagnesium and other organic products, as catalyst in the Tishchenko (85) and other reactions (86—91), in the condensation of esters (92), in alkylation reactions, and in polymeri2ations (84,91). 

The organozinc compound 2 is less reactive than an organomagnesium compound the addition to an ester carbonyl group is much slower than the addition to an aldehyde or ketone. Nevertheless the addition of 2 to the carbonyl group of unreacted a-halo ester 1 is the most frequently observed side-reaction ... 

Allenyl and 1- and 2-alkynyl sulfoxides have also been prepared by reaction of organomagnesium halides with sulfinate ester 19. 1-Alkynyl p-tolyl sulfoxides were prepared in good yield from 1-alkynylmagnesium halides plus ester 19 in toluene (equation ll)63. The corresponding organolithium compound was unsatisfactory as a... 

Methyl 2,3-epoxypropanoate can be prepared by reaction of potassium glycidate with dimethyl sulfate and one equivalent of benzyltriethylammonium chloride in methylene chloride at room temperature (65% yield).14 The reactions of this ester with organolithium or organomagnesium reagents at low temperature afford optically pure epoxy ketones14 that may be transformed via reductive amination to anti amino epoxides.15... 

Sulfonylhydroxylamines and hydroxylamine O-sulfonic acid have found wide apph-cation in synthesis of amines from achiral or chiral organoboranes and boronate esters and the hydroboration-amination methodology is successfully used for direct amination of alkenes. 0-Sulfonyloximes were also found to be good reagents for synthesis of amines from organomagnesium, -copper and -zinc reagents. 

Alkyl derivatives of the alkaline-earth metals have also been used to initiate anionic polymerization. Organomagnesium compounds are considerably less active than organolithiums, as a result of the much less polarized metal-carbon bond. They can only initiate polymerization of monomers more reactive than styrene and 1,3-dienes, such as 2- and 4-vinylpyridines, and acrylic and methacrylic esters. Organostrontium and organobarium compounds, possessing more polar metal-carbon bonds, are able to polymerize styrene and 1,3-dienes as well as the more reactive monomers. 

An important consequence of the C2 symmetry of the cyclic boronic esters is that both faces of the trigonal boron atom are equivalent. Consequently, there is only one possible intermediate borate, which can also be generated by reaction of a (dichloromelhyl)boronic ester with an organolithium or organomagnesium reagent at — 78 C2126. 

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