Aryl iodides Grignard compound reactions

Unactivated aryl iodides undergo the conversion Arl — ArCHj when treated with tris(diethylamino)sulfonium difluorotrimethylsilicate and a palladium catalyst.131 A number of methods, all catalyzed by palladium complexes, have been used to prepare unsymmetrical biaryls (see also 3-16). In these methods, aryl bromides or iodides are coupled with aryl Grignard reagents,152 with arylboronic acids ArB(OH)2,153 with aryltin compounds Ar-SnR3,154 and with arylmercury compounds.155 Unsymmetrical binaphthyls were synthesized by photochemically stimulated reaction of naphthyl iodides with naphthoxide ions in an SrnI reaction.156 Grignard reagents also couple with aryl halides without a palladium catalyst, by the benzyne mechanism.157 OS VI, 916 65, 108 66, 67. 

The corresponding reactions of diiodoacetylene are very fast even at 0° and give 75-95% yields of alkyl and aryl iodides.436 As the di-Grignard compounds from acetylene are sparingly soluble in ether, the equilibrium... 

Grignard type compounds of some lanthanide metals in the oxidation state +2 have been investigated by D.F. Evans et al. (1970, 1971). Europium, samarium and ytterbium react in tetrahydrofuran with alkyl and aryl iodides between —20 and + 30°C forming colored solutions containing mixtures of compounds, which give some Grignard-type reactions. Characterization of the compounds was done only by magnetic susceptibility measurements and some titrimetric analyses. 

Europium, samarium and ytterbium react with alkyl and aryl iodides in THE between -20 and -30°C to yield organolanthanoide(ll) iodides. The colored solutions from which no defined compounds can be obtained, show Grignard-type reactions, which are not discussed here in detail (195> 196) ... 

Classical synthetic routes to arylsilanes consist of the reaction of aryl Grignard or aryllithium compounds with silicon electrophiles and many of these routes are presented in the various reviews. Recently, metal-catalyzed reactions of aryl halides with silanes have proven to be useful routes to functionalized arylsilanes. Alami reported the first platinum-catalyzed selective silylation of aryl iodides and bromides 9 having electron-withdrawing group to give arylsilanes 10 with triethylsilane and sodium... 

Until recently the divalent organolanthanides were only briefly studied as Grignard-like reagents. D.F. Evans et al. (1970, 1971) prepared organometallic compounds of divalent ytterbium by the reaction of ytterbium metal on alkyl or aryl iodides in THE at — 20°C. Magnetic susceptibility measurements showed that 75-92% of the ytterbium is present in the divalent state. The solutions react on aldehydes or ketones as typical Grignard reagents. 

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