Diesters, symmetrical

The symmetrical diesters are produced by esterification of maleic anhydride, followed by addition of sodium bisulfite across the double bond (see... 

Carbonates are indexed in Chemicaly hstracts under carbonic acid, esters. Symmetrical diesters have the prefix di or bis. Unsymmetrical diesters are listed with the two radicals following each other. For example, ethyl phenyl carbonic diester is C2H OCOOC H. Table 6 Hsts commonly used carbonates, their Chemicaly hstracts Service Registry Number, and formulas. 

The intramolecular condensation reaction of diesters, the Dieckmann condensation, works best for the formation of 5- to 7-membered rings larger rings are formed with low yields, and the acyloin condensation may then be a faster competitive reaction. With non-symmetric diesters two different products can be formed. The desired product may be obtained regioselectively by a modified procedure using a solid support—e.g with a polystyrene 10 ... 

A divergent synthesis of tropane alkaloid ferruginine was reported by Node and coworkers [59]. The P-ketoester intermediate was prepared by a novel PLE-catalyzed asymmetric dealkoxycarbonylation (hydrolysis followed by a decarboxylation) of a symmetric tropinone-type diester (Figure 6.12). Dimethyl sulfoxide was added to the phosphate buffer pH 8 (1 9) to reduce the activity of PLE and prevent over-deal-koxycarbonylation leading to tropinone. 

Phosphorylation of cholesterol followed by the normal hydrolytic work-up gives the phosphate monoester, not the symmetrical pyrophosphate diester as previously claimed. Cholesteryl phosphorodichloridate and some related steroidal phosphorodichloridates have been prepared from the action of pyrophosphoryl chloride on the appropriate alcohol ... 

Since symmetrical pyrophosphate diesters are normally rather stable compounds, (50) has been suggested as a useful reagent for cleaving naturally occurring pyrophosphates. ... 

Scheme 7.11 shows the product structures resulting from the dithionite reduction of a simplified version of WV-15. The symmetric sulfite diester was extracted from the reaction mixture with methylene chloride. The isolation and characterization of the sulfite diester confirmed that this species can form in dithionite reductive activation reactions and provided the chemical shift for the 10a-13C center of a mitosene sulfite ester (49.37 ppm). The aqueous fraction of the reaction contained the mitosene sulfonate and trace amounts of Bunte salt, based on their 13C chemical shifts. 

Enzymatic enantioselective oligomerization of a symmetrical hydroxy diester, dimethyl /Lhydroxyglutarate, produced a chiral oligomer (dimer or trimer) with 30-37% ee [24]. PPL catalyzed the enantioselective polymerization of e-substituted-e-hydroxy esters to produce optically active oligomers (DP < 6) [25]. The enantioselectivity increased with increasing bulkiness of the monomer substituent. Optically active polyesters with molecular weight of more than 1000 were obtained by the copolymerization of the racemic oxyacid esters with methyl 6-hydroxyhexanoate. 

Boelhouwer s discovery (23) prompted a flurry of activity in this area. Baker applied the Boelhouwer catalyst to the metathesis of w-olefinic esters (88). At an ester/W molar ratio of 20/1 (68°C), symmetrical olefinic diesters were formed in 34-36% yields with concomitant elimination of ethylene. In addition, Baker identified products recovered in 3-8% yield corresponding to addition of HC1 across the terminal double bond. 

In this method, Furstner converts N-BOC protected pyrrole to the 2,5-dibromo compound (122) with NBS and this is followed by metalation and carbomethoxylation with t-butyl lithium in THF and subsequent trapping of the metalated species with methyl chloroformate to yield a pyrrole diester (123). Bromination of this diester at positions 3 and 4 with bromine in water followed by Suzuki cross-coupling with 3,4,5-trimethoxyphenyl boronic acid yields the symmetrical tetrasubstituted pyrrole (125). Base-mediated N-alkylation of this pyrrole with 4-methoxyphenethyl bromide produces the key Boger diester (126) and thereby constitutes a relay synthesis of permethyl storniamide A (120). 

Succinylosuccinic diester is cyclized according to the common route by using chlorinated or methylated aniline. Starting from anilines which are substituted in 2- or 4-position, the reaction affords the symmetrical 4,11- or 2,9-disubstitution products. Reaction with 3-substituted anilines, on the other hand, produces a mixture of both of the symmetrical 1,8- and 3,10-disubstitution products, as well as un-symmetrical 1,10-disubstituted compound. The following chart illustrates this point. 

P. Mohr, N. Waespe-Sarcevic, C. Tamm, K. Gawronska, J. K. Gawronski, A Study of Stereoselective Hydrolysis of Symmetrical Diesters with Pig Liver Esterase , Helv. Chim. Acta 1983, 66, 2501-2511. 

Although electroreduction of a mixture of esters with an Mg electrode gives a mixture of symmetrical and unsymmet-rical 1,2-diketones (Scheme 19), the reduction of diesters affords unsymmetrical 1,2-diketones as the single product (Scheme 20) [38, 39]. The selectivity of the reaction shown in Scheme 20 is highly dependent on the value of n and the best result is obtained when n = 2. 

The normal Hantzsch synthesis leads to a symmetrical product. The diesters formed may be hydrolysed and decarboxylated using base to give pyridines with less substitution. Note that we are using the ester groups as activating species to facilitate enolate anion chemistry (see Section 10.9)... 

A further approach for the synthesis of nonsymmetrically protected lanthionines is the conversion of thiosulfinates of symmetrically protected cystine derivatives into nonsymmetrically protected cystines via a reaction with a cysteine derivative and subsequently the conversion of the resulting unsymmetrically protected cystine into the nonsymmetrically protected lanthionines with a tris(dialkylamino)phosphineJ26l The oxidation of the symmetrically protected cystine, e.g. A,AT-bis(benzyloxycarbonyl)-L-cystine diethyl ester, of one stereochemical configuration to the thiosulfinate with m-chloroperoxybenzoic acid is essentially quantitative. The nonsymmetrical cystine is then formed in a subsequent step by the addition of the /V-/er/-butoxycarbonyl-L-cysteine tert-butyl ester derivative to give N-Z-N -Boc-L-cystine ethyl ferf-butyl diester. The desired 2f ,6f -lanthionine is then formed in the presence of P(NEt2)3 in yields of >50%. 

The cycloaddition of allenes to symmetrically disubstituted alkenes gives mixtures of cyclobutanes with stereochemical equilibration of the substituents. The reaction of 1,3-dimethylallenc with either diethyl fumarate or diethyl maleate produces a mixture of the /raw.v-bis(ethoxycar-bonyl)cyclobutanes.s The same nonstereoselectivity was observed for phenylallene and 1,1-dimelhylallene cycloadditions to maleic and fumaric acid diesters.9 10... 

The latter materials were based on diesters of trehalose (16a), a symmetrical disaccharide with an a-1,1 glycosidic bond (16), synthesized by Candida antarctica lipase suspended in acetone. 

The general rule based on the study of stereoselective hydrolysis of symmetrical diesters with pig liver esterase (PLE) by Tamm also predicts formation of the S enantiomer [86]. 

A study of stereoselective hydrolysis of symmetrical diesters with pig liver esterase... 

Monoderivatives of symmetrical diols.2 One possible route to these derivatives is treatment of the diol with di-n-butyllin oxide to form a stannoxane, which is then allowed to react with 1 equivalent of an acid chloride or sulfonyl chloride (equation I). L nsymmetrical diesters can be obtained by consecutive reaction of the stannoxane wilh two different reagents. 

Symmetrical diesters are easily prepared by Kolbe oxidation of half esters via decarboxylative radical dimerization [8] ... 

The pyrrolidinyl enamino keto-diester 77 reacted with 3-hydrazinylpropan-l-amine in the presence of 1 N HC1 to afford the pyrazolodiazepine 78, a key intermediate in the preparation of a glycoprotein Ilb/IIIa antagonist, in 40% yield (Scheme 35) <2003TL5867>. The requirement for the presence of 1 N HC1 to promote this process suggested that the diketo diester is the actual intermediate in the process, evaluated by examining the outcome with a mixed methyl/ethyl ester. The product was isolated as a 1 1 mixture of ester isomers, consistent with the intervention of a hydrolytic step that led to symmetrization of the electrophile. 

The complex WOCI4—Cp2TiMe2 was used for the metathesis of ethyl oleate (51) to give diethyl 9-octadecenedioate (52). Civetone (53) was synthesized by the Dieckmann condensation of this diester, followed by decarboxylation [20], Homometathesis of terminal alkenes is useful, because it yields symmetric internal alkenes and ethylene, which can be removed easily. Metathesis of 10-undecenoate (54) proceeds smoothly to give the diester 55 [20],... 

Monoesters of symmetric dicarboxylic acids can be prepared either by monoesterification of a diacid [1] or by monosaponification of a diester. Dicarboxylic acids which can form five- or six-membered cyclic anhydrides are readily transformed into monoesters via these intermediates, but for diacids which cannot be converted into such cyclic anhydrides monosaponification of diesters seems to be more reliable than selective monoesterification. Monoesters or monoamides of succinic, maleic, glutaric, or related diacids can be rather unstable, because of the dose proximity of a carboxyl group (see Section 3.3). 

Symmetric diesters with enantiotopic alkoxycarbonyl groups can sometimes be monosaponified enantioselectively by use of esterases (Scheme 10.2) [5]. Enzymes... 

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