Arylation methyl benzoate

The reactions were conducted in a custom-made 0.5 x 2.0 in screw-capped stainless steel vial and milled with an 0.250 in aluminum oxide ball-bearing in a Spexx certiprep mixer/mill 8000 M for approximately 17 h. Various para-substituted aryl methyl benzoates were reduced using a 5 1 ratio of lithium chloride sodium boro-hydride. At the conclusion of the reaction, the products were washed with 10% HC1 and the remaining solids were dried over a Hirsch funnel. Liquid products were isolated by extraction from a minimal amount of ethyl acetate. 

Carbanions derived from optically active sulfoxides react with esters, affording generally optically active )S-ketoesters ° . Kunieda and coworkers revealed that treatment of (-t-)-(R)-methyl p-tolyl sulfoxide 107 with n-butyllithium or dimethy-lamine afforded the corresponding carbanion, which upon further reaction with ethyl benzoate gave (-l-)-(R)-a-(p-tolylsulfinyl)acetophenone 108. They also found that the reaction between chiral esters of carboxylic acids (R COOR ) and a-lithio aryl methyl sulfoxides gave optically active 3-ketosulfoxides The stereoselectivity was found to be markedly influenced by the size of the R group of the esters and the optical purity reached to 70.3% when R was a t-butyl group. 

The aryl rings of acetophenone and methyl benzoate are preferentially hydrogenated, with only minor reduction of the substituents. In contrast, hydrogenation of nitrobenzene, under essentially the same conditions, produces aniline and nitro-cyclohexane in ca. 9 1 ratio, with an overall conversion of >79%. This observation has additional significance when compared with the hydrogenation of the nitro derivative of vinylbenzene (Table 11.25). In all cases, it is the C=C bond which is hydrogenated and, only after a prolonged reduction time, is 1-nitro-2-phenylethene completely reduced to the aminoethane [4],... 

When aryl rings were used as bridgeheads (Section 2.2), a tetrafunctional-ized pyridine 28 (s. Scheme 5), 1,10-phenanthroline 18 (s. Scheme 4), benzoic acid 35 (s. Scheme 6) or methyl benzoate 36 (s. Scheme 6) was reacted with two... 

Treatment of 2-(2-methylphenyl)-5,5-dimethyl-l,4,5,6-tetrahydropyrimi-dine (279) with butyllithium in the presence of /V,/V,Al, /V -tetramethyleth-ylenediamine (TMEDA) in tetrahydrofuran at 0°C under nitrogen, then with methyl benzoates at -50°C gave 6-aryl-6-hydroxy-3,4,6,7-tetrahydro-2//-pyrimido[2,l-a]isoquinolines (280), which gave 6-ary 1-3,4-di hydro-2//-pyrimido[2,l-a]isoquinolines (281) with heating in toluene in the presence of p-toluenesulfonic acid (93JMC3098). 

Aminolysis of phenyl dithioacetates,8 pyridinolysis of O-ethyl dithiocarbonates,9 reaction of pyrrolidine with O-ethyl 5-aryl dithiocarbonates,10 aminolysis of chlorothionformates,11 pyridinolysis of alkyl aryl thioncarbonates,12 reaction of anionic nucleophiles with nitrophenyl benzoate and its sulfur analogues,36 hydrolysis of methyl benzoate and phenyl acetate containing SMe, SOMe and S02Me substituents,42 solvolysis of phenyl chlorothioformate,79 synthesis of new thiadiazoles,124 examination of a neighbouring sulfonium group in ester hydrolysis,136 hydrolysis of V-type nerve agents,250 and the reactions of peroxymonosulfate ion with phosphorus(V) esters have all been looked at previously in this review. 

Chiralcel OJ Cellulose tris(4-methyl benzoate) Aryl methyl esters, aryl methoxy esters ... 

Reaction of methyl benzoate (144) with a palladium acetate/heteropolyacid mixture has been studied by Lee and coworkers [98]. They showed that aryl-aryl coupling occurs mainly at the 2-2 positions in the presence of various heteropolyacids (HPA e.g. H3PM012O40, H5PM09V3O40, H5PM010V2O40, etc.) (Scheme 34). The selectivity in favor of the 2-2 coupling product is between 53 and 84 %, but the conversions are low (0.48 to 6.93) due to deactivation of the catalyst. The observed selectivity can be rationalized in terms of formation of the (T-palladium complex 146 with stabilization by the carbonyl group (Figure 3). 

Methyl benzoate (aryl ester) 3-Methylbutanal (alkane aldehyde)... 

Numerous examples of postsynthetic modifications at the dendritic periphery have been explored. In early work, Hawker et al. investigated the hydro-genolysis and subsequent modification of benzyl-protected poly(aryl ester) dendrimers473 and later the saponification of Frechet-type dendrimers with p-methyl benzoate end groups to afford an anionic carboxylated periphery.41 The isophthalate ester end groups proved to be especially versatile (Scheme 28)... 

Palladium(II) acetate micro-encapsulated in polyurea is an economical and versatile heterogeneous catalyst for a range of phosphine-free cross-coupling reactions in both conventional solvents and supercritical carbon dioxide. The catalyst can be recovered by simple filtration and recycled up to four times [93]. The potential of these materials has been demonstrated by their efficacy in Suzuld-type couplings. Investigations have centered upon carbonylation reactions to prepare aryl esters from commercially available aryl iodides. Treatment of iodo-methyl benzene tvith 3 mol% of catalyst in butanol and triethylamine at 90 °C under an atmosphere of carbon monoxide afforded butyl-methyl benzoate in an excellent yield of 89% in 16 h. 

Particular attention has been devoted this year to the study of fluorinated aryl azides. This interest stems from their potential use as photoaffinity probes due to the ease with which perfluorophenyl nitrene undergoes C-H bond insertion. Perfluorin-ated azide derivatives of methyl benzoate afford photochemically... 

The reactive intermediate Fe(dmpe)2 cleaves the C—H bonds of other aromatic substrates, but the reactions are complex. The final products with anisole or methyl benzoate are methyl derivatives derived from cleavage of their respective O—CH3 bonds. Chlorobenzene gives a transient aryl hydride, but the ultimate product is the phenyliron chloro complex. Both Ru(dmpe)2H(CioH7) and Os(dmpe)2H(CioH7) are also in equilibrium with their respective M(dmpe)2 intermediates, but the equilibria are very sluggish and of little synthetic utility. An alternative approach to these species is photochemical activation of Fe(dmpe)H2 the products can be obtained more cleanly, and the intermediate Fe(dmpe)2 cleaves even aliphatic C—H bonds. 

Side chain benzoyloxylation of aryl methyl ethers. Activation of the C-H bond is achieved in the presence of oxygen and BZ2O, giving excellent yields of the benzoates. 

Inoue et al. have described their study of the singlet sensitized isomerization of cyclo-octene. They report that the use of methyl benzoate or other aryl esters results in the anomalously high trans-cis ratio of 0.25. This result is only anomalous if a triplet mechanism is operative but the authors have shown that in this instance a singlet state is the active species. The same sensitizer has been used in a study of the photochemical behaviour of the diene (44), which is converted into the isomer (45) and subsequently into (46). ... 

Our preliminary studies show that the catalyst system can tolerate at least some functionalities on the arene thus, while substrates containing unprotected -OH or COoH groups are hydrogenated only to a small degree or not at all, aryl-ethers (anisole), -esters (methyl benzoate), -ketones (acetophenone, benzophenone), and N,]V-dimethylaniline are all hydrogenated. In general, no products corresponding to states of intermediate reduction (cyclohexenes or cyclohexadienes) are detected. 

Conjugation with a Carbonyl Group (a,p Unsaturation or Aryl Substitution). The C=0 stretching vibrations are shifted by about 15 to 25 cm to lower frequencies with unsaturation or aryl substitution, as predicted in Section 2.14A (Conjugation Effects, p. 52). The spectra of both methyl methacrylate (Fig. 2.48) and methyl benzoate (Fig. 2.50) show the C=0 absorption shift from the position in a normal ester, ethyl butyrate (Fig. 2.47). Also notice that the C=C absorption band at 1630 cm in methyl methacrylate has been intensified over what is obtained with a nonconjugated double bond (Section 2.10B). 

Considerable amount of dehalogenation product, methyl benzoate was isolated For orrto-substituted aryl bromides and iodides, 20-50 mol% of Ni(PPh3)2Br2 was used 2-Iodoanisole gave anisole in almost quantitative yield. 

In 1970 Hashimoto published a report on the reaction of potassium hexacy-anodinickelate with organic halides in aqueous solutions [295]. Benzyl bromides were transformed into dibenzyl ketones in the presence of CO in a water-acetone solution. If the reaction was carried out in a water-methanol solution, trans-fi-bromostyrene was transformed into methyl trani-cinnamat. Surprisingly, cinna-maldehyde was also formed in a 10 % yield (Scheme 2.47). The reaction of nickel carbonyl [Ni(CO)4l with organic halides was studied by Bauld in 1963 [296]. Aryl iodides were reacted with Ni(CO)4 in methanol and produced the corresponding methyl benzoate in good yields. If the reaction was carried out in THF, arils were formed. The reaction of allyl halides with Ni(CO)4 in the presence of MgO will produce but-3-enylsuccinic acid [297]. 

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