Phenyl Grignard reagent

The phenylation of styrene with phenyl Grignard reagents as a hard carbon nucleophile proceeds in 75% yield in the presence of PdCl2, LiCl, and K2CO3 at room temperature to give stilbene (207). Selection of the solvent is crucial and the best results are obtained in MeCN. The reaction can be made catalytic by the use of CuCl2[197]. Methyllithium reacts with styrene in the presence of Pd(acac)2 or Pd(OAc)2 to give /3-methylstyrene (208) in 90% yield[198]. 

The epimeric 3-methyl and 3-phenyl steroids (17) and (18) have been obtained by reaction of methyl and phenyl Grignard reagents with 4-chloro-17l -hydroxyandrost-4-en-3-one (16). 

Octaethyl and tris(pentafluorophenyl) corroles, known as oec and tpfc, respectively, are also efficient for the stabilization of P(VI) phosphorus [53,54]. The electron-rich oec reacts with PCI3 to form (oec)P=0 40 that can be further derived into dihydrido 41a, dimethyl 41b and diphenyl 41c compounds by reduction with LiAlH4 and reactions with methyl and phenyl Grignard reagents. 

The cycloaddition behavior of 2 in the presence of 1,3-cycloheptadiene [4] is comparable to that just described above for cyclohexadiene. Treatment of the Si-dichloro substituted [2+2] adducts 14 with phenyl Grignard reagent leads to the crystalline derivative -14a. 

N-Methyl-2-phenyl-A2-tetraJiydropyridine and similar compounds have previously been prepared by the hydrolysis and decarboxylation of a-benzoyl-N-methyl-2-piperidone3 and by the addition of phenyl Grignard reagents to N-methyl-2-piperidone followed by dehydration.4 Both of these methods require that a heterocyclic ring already be present in the system. In contrast, this procedure offers a new flexible route to the construction of five- or six-membered heterocyclic rings which may easily be incorporated into a larger polycyclic product. Several examples of this process that can be cited to demonstrate this utility are... 

Recently, a direct kinetic study on the amination of substituted phenyhnagnesium bromides using Af,Af-dimethyl O-mesitylenesulfonyl hydroxylamine 3b as amination reagent has been reported by Erdik and Ate Ulkii . Rate data, the Hammett relationship and activation entropy support an Sn2 displacement of the carbon nucleophile on the electrophilic nitrogen. These results are consistent with the competition kinetics for electrophilic amination of substituted phenyl Grignard reagents with O-methylhydroxylamine In. ... 

Osmium tetroxide reacts with phenyl Grignard reagent to produce a reactive intermediate, serving as a synthetic route to prepare polyphenyl osmium complexes. For example, reaction with o-tolyl magnesium bromide, o-tolMgBr, forms a purple, tetracoordinated osmium ort/io-tolyl complex, Os(o-tol)4, which reacts with trimethylphosphine or carbon monoxide to yield osmium n-aryl complexes. 

Hydroxyethyl)carbazole can be oxidized with copper(II) oxide-potassium hydroxide at 240°C to the carbazol-9-ylacetic acid the benzoate ester of the alcohol was cleaved to regenerate alcohol using phenyl Grignard reagent. The 9-acetic acid is also produced by alkaline hydrolysis of the corresponding nitrile. ... 

A number of authors have studied the reductive termination step. The classical work by Hermann and Nelson (121) showed that the reduction of the titanium in alkyltitanates occurred readily with the more alkylated species. The same authors (122) showed that the stability of the alkyl metal decreased markedly when the number of alkyls per metal atom increased. This is parallel to increased anionicity of the alkyl. Vanheerden (123) pointed out that the disproportionation of alkyl-titanium was bimolecular. Cotton (124) showed that the coupling occurs when phenyl Grignard reagents are mixed with various transition metal salts. This is through disproportionation or combination of the alkyl radicals. 

Compared with asymmetric ethylation, reports on asymmetric phenylation are limited. We disclosed the enantioselective phenylation using diphenylzinc prepared in situ from phenyl Grignard reagent and zinc chloride. This method needs a stoichiometric amount of chiral amino alcohol DBNE 18 but good ee of 82% was achieved [32], A catalytic phenylation was examined using planar chiral compound 1 based on ferrocene, and chiral diaryl carbinols of moderate ee were provided from diphenylzinc and 4-chlorobenzaldehyde (Scheme 10) [33]. A catalytic and highly enantioselective phenylation was realized by binaphthyl-based chiral catalyst 23. In this reaction, the addition of 2 equivalents of diethyl-zinc against catalyst increases the yield and ee [34]. Recently, chiral amino alcohol DPMPM 9 was also reported to be an efficient catalyst for asymmetric phenylation [35]. 

Thus, the two phenyl substituents arise by addition of a phenyl Grignard reagent to an ester of cyclopropanecarboxylic acid. 

Leazer, J. L. Cvetovich, R. Tsay, F.-R. Dolling, U. Vickery, T. Bachert, D. An improved preparation of 3,5-bis(trifluoromethyl)acetophe-none and safety considerations in the preparation of 3,5-bis(trifluoromethyl)phenyl Grignard reagent. J. Org. Chem. 2003, 68, 3695-3698. 

Arsenic was analysed chromatographically by Schwedt and Russel [617], It was first extracted from biological material into chloroform as the dithiocarbamate, which was converted into triphenylarsine(III) by the treatment with phenyl-Grignard reagent. In this form it was subjected to GC analysis with the use of an FID. Concentrations of arsenic down to 2 jug per gram of biological sample was measured. 

Completely aromatic, hyperbranched polyphenylenes were synthesized as monodendrons from AB2 type monomers by Kim and Webster [111, 112]. These dendrimers were prepared either by the homocoupling of 3,5-dibromophenyl boronic acid under modified Suzuki conditions, or by aryl-aryl coupling reactions involving 3,5-dihalo-phenyl Grignard reagents in the presence of Ni(II) catalysts as shown in Scheme 7. 

A well known reaction in lead chemistry is the synthesis of PhsPb PbPhs from phenyl Grignard reagent and lead (II) halides. The mechanism for this reaction is presumed to involve the formation of diphenylplumbylene, which then oligomerizes and disproportionates to hexaphenyldilead and metallic lead. However, repeating the above reaction at low temperature led to the isolation of unexpected oligomeric lead... 

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