Organomagnesium reagents, preparation

Reactions of highly functionalized heterocyclic organomagnesium reagents prepared through halogen-metal exchange 03AG(E)4302. 

As with organomagnesium reagents, there is usually loss of stereochemical integrity at the site of reaction during the preparation of alkyllithium compounds.25 Alkenyllithium reagents can usually be prepared with retention of configuration of the double bond.26,27... 

The preparation of ketones proceeds conveniently by reaction of imidazolides with organomagnesium reagents, as shown in Table 14-6 for several examples of purely aromatic, aromatic-aliphatic, and purely aliphatic ketones. The yields are very satisfactory even for purely aliphatic ketones, since in this case, too, alcohol formation is completely suppressed.t851,t861... 

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... 

MANGANESE-COPPER-CATALYZED CONJUGATE ADDITION OF ORGANOMAGNESIUM REAGENTS TO a,p-ETHYLENIC KETONES PREPARATION OF 2-(1,1-DIMETHYLPENTYL)-5-METHYL-CYCLOHEXANONE FROM PULEGONE (Cyclohexanone, 2-(1,1-dimethylpentyl)-5-methyl-)... 

Mixed lanthanide-alkali chlorides, LnCl3.2LiCl (Ln = La, Ce, Nd) can be readily prepared as 0.5 mol dm-3 solutions in THF.235 They act as improved promoters of addition of organomagnesium reagents to ketones, and also to aldimines, and in addition have been found to promote organolithium addition. 

Oestreich, M. Hoppe, D. Stereospedfic preparation of highly enantiomerically enriched organomagnesium reagents. Chemtracts -Organic Chemistry 2001, 34, 100-105. 

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