Arylmagnesium chlorides

Allenes 185 react with arylmagnesium chlorides in the presence of trialkylsilyl chlorides and a Pd° catalyst, furnishing substituted allylsilanes 186 with high (Z)-stereoselectivity (equation 111). Alkyl halides afford in this reaction mixtures of regioisomeric trisubsti-... 

A-Boc-leucinal may react with allyl- and alkenyhnagnesium hahdes giving syn- and awf/-products in ca 9 1 ratio. This method was used for the asymmetric synthesis of important amino acids like statine and norstatine. An enantioselective desymmetrization of anhydrides was reported. Arylmagnesium chlorides react in toluene in the presence of (—)-sparteine (1 equiv.) with 3-substituted glutaric anhydrides 215, giving aryl ketones with 87-92% ee (equation 145). ... 

Process and catalysts for the preparation of bisaryl compounds by the coupling of arylmagnesium chlorides with aryl chlorides in the presence of phosphine ligands, Poetsch, E. Meyer, V. DE4326169A1, 1993. 

For simple alkyl- and arylmagnesium chlorides, bromides and iodides, the following broad generalizations may be made ... 

In contrast, cross-coupling between arylmagnesium chlorides and aryl bromides is catalysed by nickel(n) chloride, without any bidentate ligand [35] ... 

Tetrahydrofuran is an important solvent, used, for example, in reductions with lithium aluminum hydride, in the preparation of arylmagnesium chlorides (Sec. 

Similar work was reported by Liang etal. [166] in 2012 by using an amido phosphane chelate with a pendant amine arm as a ligand to form a nickel complex. A variety of alkyl and arylmagnesium chlorides were coupled with iodoarenes, bromoarenes, and chloroarenes using these nickel complexes under mild conditions. 

The products of the exchange reaction, arylmagnesium chloride-lithium chloride complexes, are more reactive and much more soluble than usual aryl Grignard reagents. They undergo a number of useful transformations such as Pd- or Ni-catalyzed cross-coupling, 2 addition to carbonyl compounds, or electrophilic amination at low temperatures. 

Aryl and heteroaryl bromides and iodides react analogously . The formation of arylmagnesium chlorides, however, requires more drastic reaction conditions such as higher reaction temperatures and reaction times for completion. This allows discrimination between Cl- and Br- or 1-substituents, as demonstrated by the syntheses of 2-chloro- and 2,6-dichlorobenzoic [ C]acids from 2-bromochlorobenzene and 2,6-dichloroiodo-benzene, respectively. ... 

These reactions complement recently developed palladium(0)amination reactions [146,147,148] and related procedures using a copper(I) [149] - or ni-ckel(O) [151] - catalysis. As indicated above, the mild reaction conditions are compatible with a range of functional groups. Functionalized arylmagnesium chlorides such as 309 prepared by an I/Mg-exchange readily undergo addition reactions to aryl oxazolines. The addition-elimination of 309 to the -methoxy aryloxa-zoline followed by an ortHo-lithiation and substitution with ethylene oxide leads to a polyfunctionalized aromatic intermediate 310 for alkaloid synthesis (Scheme 4.68) [165]. 

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