Reaction of Organometallic Reagents

The simple chiral lithium alkoxide 5 was applied to the Michael reaction of methyl phenylacetate with methyl acrylate to give the corresponding adduct in 84% ee (Eq, (12.6)) [19]. The catalytic enantioselective Michael reaction was also effected by the chiral alkoxide 5. 

1 Reaction of Organolithium Reagents Using External Chiral Ligands 

Due to the high nucleophilicity of the organolithium reagent, a bulky reagent such as dithiane used to be the Michael donor [20], Recent progress has been made 

The first prominent catalytic asymmetric Michael-type addition reaction of an organolithium reagent was shown by the reaction of 1-naphthy[lithium with 1-fluoro-2-naphthylaldehyde imine in the presence of 6 to afford the binaphthyls in high ee. Only catalytic amounts of 6 (0.05 mol%) effects the reaction to give 82% ee, in which an enantioselective Michael-type addition-elimination mechanism is operative (Eq. (12.12)) [31], 

A chromium complex of benzaldehyde imine is also a good substrate for the Michael-type addition of organolithium reagents mediated by a stoichiometric amount of the chiral diether 6 in toluene to give the corresponding product in up to93%ee(Eq. (12.13)) [32]. 

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Carbon-Carbon Bond-Forming Reactions of Organometallic Reagents... 

C. Alkyl and Aryl Derivatives.—Reactions of organometallic reagents, such as methyl-lithium, with fluorocyclophosphazenes are, in general,... 

Treatment of 19b with phenylmagnesium bromide gives diphenylacetylene (66) and the salt of benzenesulfmic acid Lithium aluminium hydride reacts with 19b similarly. These ring-opening reactions are similar to the reactions of organometallic reagents with the analogous thiirane dioxides (equation 17 above). 

The reactions of organometallic reagents with chlorocyclophospha-zenes are quite complex and depend on several variables, such as (a) the ring size of the cyclophosphazene, (b) the nature of the organometallic reagent, and (c) the reaction conditions including the type of solvent used, the temperature of the reaction, etc. (10). 

The use of chiral chelating agents in reactions of organometallic reagents with carbonyl compounds has been intensively investigated (134-138). However, the influence of such chiral addends in the aldol process has not met with much success. In the presence of the... 

Each of the following compounds can be prepared from reactions of organometallic reagents and readily available starting materials. Identify the appropriate organome-... 

These groups are stable to a number of reaction conditions, including generation and reaction of organometallic reagents.89 They are readily removed by hydrolysis. 

The Reaction of Organometallic Reagents with Epoxides 3(OCJ-seco-Alkyl-de-alkoxy-substitution... 

With the usual reaction of organometallic reagents with acid derivatives (ester or acid chloride), the starting materials can add two equivalents of organometallic compound. The ketone generated after the first addition is quite reactive, and there is quite no selectivity between it and the starting acid derivative ... 

Table 10 Conditions of the reaction of organometallic reagents with 3-monosubstituted /3-sultams 77...

III. REACTIONS OF ORGANOMETALLIC REAGENTS IN THE PRESENCE OF TRANSITION METAL CATALYSTS... 

Key Mechanism 10-1 Grignard Reactions 443 Summary Grignard Reactions 450 10-10 Side Reactions of Organometallic Reagents Reduction of Alkyl Halides 451... 

Side Reactions of Organometallic Reagents Reduction of Alkyl Halides... 

The use of aminosulfites in the synthesis of o.p. sulfoxides was described for the first time in 1973 by Wudl and Lee,98 using ephedrine as chiral auxiliary. In 1991, Benson and Snyder reported a modification of the Wudl and Lee procedure, obtaining o.p. sulfoxides in high yield by sequential displacement reactions of organometallic reagents on the 1,2,3-oxathiazolidine-S-oxide (aminosulfite 70), obtained from ephedrine and thionyl chloride.99... 

The reaction of organometallic reagents such as Grignard reagents or cuprates with chiral menthyl sulfinates57-63,64. known as the Andersen reaction65, yields optically active sulfoxides. 

Reaction of organometallic reagents with aldehydes and ketones... 

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