Dimethyl-3-hexenedioate

An improved method for the preparation of methyl 2-oxo-5-vinyl-cyclopen-tanecarboxylate (389) by treatment of dimethyl ( )-2-hexenedioate (390), with the cuprate made from vinyllithium and copper(I) cyanide (77-85%), led to a short synthesis of mitsugashiwalactone (391) (Scheme 34), another noriridoid isolated from Boschniaka rossica Borohydride reduction and dehydration gave methyl 5-vinyl-l-cyclopentenecarboxylate (392), and this could be cyclized by hydroboration and extended treatment with hydrogen peroxide—conditions for the highest yield in the cyclization seem to be with hydroboration in base— then a separate acid-catalyzed cyclization. The methyl group was added with lithium dimethyl cuprate. ... 

In 2011, Matsuoka et al. [78] reported the NHC-catalyzed highly selective tail-to-tail dimerization of methyl methacrylate giving dimethyl 2,5-dimethyl-2-hexenedioate... 

Also the dimerization of acrylates has found great interest in munerous academic and industrial research groups. Alderson and co-workers of Du Pont [48] investigated the dimerization of methyl acrylate in the presence of rhodium chloride. By heating a solution of methyl acrylate in methanol to 140 °C some dimethyl 2-hexenedioate (= dimethyl-a-dihydromuconate) was formed (Equation 42). 

Ruthenium-catalyzed hydrodimerization of acrylonitrile under hydrogen atmosphere to give adiponitrile (393) is a useful coupling reaction [154], Dimethyl hexenedioates (394a and 394b) are formed by dimerization of methyl acrylate by Pd, Ru and Rh catalysts. In particular the catalyst prepared by the treatment of RuC12 with Zn and... 

For example, the tail-to-tail dimerization of methyl acrylate was catalyzed by ruthenium complexes such as RuHCl(C0)(Pz-Pr3)2/CF3S03Ag or even RuC13 and gave dimethyl hexenedioate isomers. Efficient catalytic systems such as Ru(rf-naphthalene)(COD)/CH3CN, where COD is cyclooctadiene, selectively led to the diester 2 in 75% yield [1] (Eq. 1). 

RhCp (C2H4)(CH2CH2- -H)] which is prepared by protonation of RhCp (C2H4)2, is a highly active catalyst for tail-to-tail dimerization of methyl acrylate to dimethyl hexenedioates (eq (51)) [61]. 

A, Dimethyl (s)-2-hexenedioate. A 100-roL, one-necked, round-bottomed flask is capped by a septum, swept with dry nitrogen and flame-dried. The flask is charged with methyl acrylate (50 ml, 0.55 mol. Note 1), then anhydrous lithium tetrafluoroborate (9 g, 0.096 mol, Note 2), and finally tetrakis(acetonitrile)palladium tetrafluoroborate (1.33 g, 0.003 mmol. Note 3). The mixture is stirred briefly until homogeneous. It is warmed under nitrogen in a 40°C-o11 bath for 72 hr (Note 4) and then allowed to cool to room temperature. The mixture is added to saturated aqueous sodium bicarbonate (100 mt) and extracted with ether (3 x 50 mt). The combined ether extracts are dried over anhydrous magnesium sulfate, filtered and concentrated to an oil with a rotary evaporator. The residue is distilled through a lO-cm... 

Dimethyl (E)-2-hexenedioate 2-Hexenedioic acid, dimethyl ester,... 

Dimethyl 3,3a,3b,4,6a,7a-hexahydro-3,4,7-metheno-7H-cyclopenta[a]pentalene-7,8-dicarboxylate 3,4,7-Metheno-7H-cyclopenta[a]pentalene-7,8-dicarboxylic acid, 3,3a,3b,4,6a,7a-hexahydro-, dimethyl ester (53282-97-6), 68, 198 Dimethyl (E)-2-hexenedioate (70353-99-0), 66, 52, 53, 59 N,0-Dimethylhydroxylamine hydrochloride Methylamine, N-methoxy-, hydrochloride Methanamine, N-methoxy-, hydrochloride (6638-79-5), 67, 69 N,N-Dimethylisobutyramide, 66, 117, 118... 

Dimethyl-3-hexenedioic acid (171) was also prepared by an intermolecular diacylation of the dibromide 170 with 2-lithio-l,3-dithiane (161), followed by deprotection and final oxidation (Scheme 48)214. 

D. trans-4,7,7-Tricarbomethoxy-2-phenylsulfonylbicyclo[3.3.0]oct-1-ene. In a flame-dried, 2-L, three-necked, round-bottomed flask equipped with a magnetic stirrer, dropping funnel, and nitrogen inlet, is placed 1.44 g of sodium hydride (60% in oil, 36.0 mmol) which has been washed twice with 50 mL of hexane and then suspended In 500 mL of anhydrous THF. To the above mixture is added 7.59 g (33.0 mmol) of dimethyl (E)-5-methoxycarbonyl-2-hexenedioate in 50 mL of THF. After being stirred at 0°C for 30 min, a solution containing 10.02 g (30.0 mmol) of 2,3-bis(phenylsulfonyl)-1,3-butadiene in 900 mL of anhydrous THF is added over 30 min. The solution is stirred for 10 min at 0°C and then quenched with 100 mL of a saturated aqueous ammonium chloride solution. The solvent is removed under reduced pressure, and... 

Dimethyl (E)-5-methoxycarbonyl-2-hexenedioate (11) 3-Butene-1,1,4-tricarboxylic acid, trimethyl ester, (E)- (11) (93279-60-8)... 

Conjugate addUion-cyclization. 3-Substituied 2-carbomethoxycyclopentanones are prepared conveniently in one step from dimethyl (2E)-hexenedioate by conjugate addition of lithium dialkyl cuprates or higher-order cyan[Pg.348]

Butadiene, which is bound in a n -manner to iron, reacts stoichio-metrically with carbon dioxide to form an allyl carboxylato complex in yields up to 75 % [38]. This allyl complex shows a dynamic behaviour Presumably three isomeric structures exist in solution, two of them with a n"-allyl bonding (Figure 16). Subsequent reactions of the allyl carboxylato complexes yield carboxylic acids. Acidic hydrolysis in methanol at -30°C gives methyl-3-pentenoate and methyl-4-pentenoate in a ratio of 10 1. If the iron allyl complex reacts with further carbon dioxide at 90 C, a second insertion of CO2 into the Fe-C-bond occurs after hydrolysis with hydrochloric acid in methanol the Z- and E-dimethyl esters of 3-hexenedioic acid are formed. 

Similar to the iron chemistry (compare Chapter 2.3), also nickel complexes allow the reaction of one molecule of butadiene with two molecules of CO2 yielding a,u-dicarboxylic acids [48]. In the reaction of butadiene and CO2 in the presence of nickelbis(cyclooctadiene) and tetramethylethylenediamine first a nickelamonocarboxylate is formed (Figure 19). By further treatment with carbon dioxide and by addition of pyridine a nickeladicarboxylate complex is obtained in yields up to 72 %. Decomposition of the complex with methanol/hydrochloric acid gives cis-dimethyl-3-hexenedioate. 

A more selective catalyst system was found by Barlow et al. [49]. Using dichlorobis(benzonitrile)palladium a yield of 93% dimers was obtained. The product contained approximately 90% linear dimers with dimethyl trarw-2-hexenedioate (67%) as the major isomer, while the next most prevalent isomer was dimethyl trans-3-hexenedioate. The svuprising selec-... 

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