Dimethyl methylmalonate

Interestingly, the allylation of a stabilized carbon nucleophile has been found to be reversible. Complete isomerization of dimethyl methylmalonate, involving bis-allylic C—C bond cleavage, from a secondary carbon 38 to a primary carbon 39 was observed by treatment with a Pd catalyst for 24 h. The C—C bond cleavage of a monoaliylic system proceeds slowly[40]. 

An interesting feature is the sometimes observed pressure dependence of the reaction. The Michael addition of dimethyl methylmalonate 12 to the bicyclic ketone 13 does not occur under atmospheric pressure, but can be achieved at 15 Kbar in 77% yield ... 

Another example of a case where acid-base chemistry competes with cyclization is found in efforts to construct an analog of the Corey lactone [45], The enantiomerically pure unsaturated ester 91 was assembled and subjected to the conditions indicated in Eq. (26). In this instance, dimethyl methylmalonate was used as the proton donor to avoid 1,4-addition of the conjugate base to 91. Cyclization afforded a combined 77% isolated yield of the y-hydroxy ester 92 and the lactone 93 the former could be converted to the lactone in the... 

Equally, a 1.5 1 mixture of cis- and frans- 1,3-dibromo propene reacts with sodium dimethyl methylmalonate to furnish the vinyl bromo derivative 79 in excellent yield, which in turn is transformed in a one-pot fashion to a 1.5 1 mixture of enyne 80 or the corresponding Suzuki products 81 and 82 (Scheme 24). Interestingly, (( )-3-bromo-propenyl)-tributylstannane furnishes the vinyl stannane 83 upon allylic substitution that instantaneously is subjected to the conditions of a Stille coupling with iodo benzene to give the sequence s product 84 in 68% yield (Scheme 25). 

A cyclopentadienylcopper-fcr/-butyl isocyanide complex catalyzes the Michael addition of dimethyl methylmalonate to acrylonitrile at room temperature to give an S6% yield of the adduct 249). As the CU2O—BNC complex can also catalyze the addition of indene to methyl acrylate, the intermediate is most likely an organocopper complex. The reactions and kinetic data support the mechanism given by Eq. (118) to (120), involving metalation and nucleophilic attack by the carbanion on the olefin within the complex. Displacement of a solvent ligand by the olefin and coordination of the latter to the copper species are essential features of the mechanism. The rate of reaction is decreased if the compound with the... 

However, the anion of dimethyl methylmalonate preferentially attaeks the terminal primary center to give 3. 

Dimethyl 2-vinylcyclopropane-l,l-dicarboxylate reacted with the anion generated from dimethyl methylmalonate via the 1,5-addition product to give a cyclopentanone derivative 10. ... 

Oxidative radical cyclization sequences have also been used to generate 1,2-fused indoles. Treatment of amides 152 and 154 with dimethyl methylmalonate in the presence of manganese(III) acetate and sodium acetate in acetic acid, gave the expected cyclized product in 63% and 40%, respectively [97]. The proposed mechanistic sequence involves the intermolecular addition of the dimethyl methylmalonate radical to the tethered exocyclic alkene followed by cyclization and finally rearomatization. Byers and coworkers also achieved a similar cyclization on the C-2 position of the indole when a 3-acylindole was subjected to these oxidative cyclization conditions. 

Allylic geminal dicarboxylates 285 are prepared by Pd-catalyzed reaction of propargyl acetate 284 with AcOH [104], Two products 287 and 288 are obtained from gem-allylic compounds 286, and 288 is an allylic ester and undergoes the second allylation. Several applications to asymmetric syntheses have been reported [48]. Reaction of 289 with dimethyl methylmalonate afforded 290 with 95% ee. 

In case of functionalization by soft nucleophiles, poly(ferrocenyl(3-iodo-propyl)methylsilane) 3b is a suitable starting material. Malonic ester enolates such as dimethyl methylmalonate anion or dibenzyl methylmalonate anion smoothly react to produce the corresponding polyesters with quantitative conversions. By using hydrolytically labile ester enolates, such as methyl trimethylsilyl methylmalonate anion, one can easily convert the corresponding pendent ester groups into car-boxylate salts, thus forming an organometallic polyanion (see Scheme 3). 

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