Diallyl malonate

Very recently, Leitner has reported cationic nickel(n) catalyst systems for the cycloisomerization of diethyl diallyl malonate that shows high activities and regioselectivities for the formation of diethyl 3-methylene-4-methylcyclo-pentane-l,l-dicarboxylate with ee values up to 80% when using Wilke s azaphospholene ligand.355... 

Preparation of the intermediate for Allobarbitone (diethyl diallyl malonate). Diethyl malonate is dissolved in anhydrous alcohol and treated with one mole of clean sodium meted per every one mole of the ester. To this solution add one mole of allyl chloride and reflux for about 4 hours. Another equimolar ratio (1 mole of sodium per mole of ester) of sodium is added, followed by the same ratio of allyl chloride (1 mole per 1 mole), and this mixture is boiled for 2 hours. The alcohol is removed by distillation and the ester is extracted with benzene and distilled or evaporated in vacuo, recrystallized with a suitable "dry" solvent, and filtered. Evaporate again to remove traces of solvent. Keep this product, and any other substances that require dry reagents or solvents, stored away from contact with the atmosphere. When evaporating, filter the air coming into the evaporating vessel with a suitable drying agent. Use a little common sense. 

Figure 1.11 provides an example of H NMR monitoring in the Pd-catalyzed cy-doisomerization of dimethyl diallyl malonate, 39 [28]. The kinetic profile reveals a pronounced induction period after which the exocydic alkene 40a is formed predominantly as the kinetic product. A hydropalladation mechanism was proposed on the basis of NMR experiments, and the transient spedes 41, formed by allylpalla-dation of the coordinated diene, could be detected and identified with the help of and labeling. The hydride Pd catalyst, 42, would be generated from 41 by water-promoted P-hydride elimination. The observed induction period is assodated with the formation of the Pd-hydride 42. 

Figurel.il Pd-catalysed cycloisomerisation ofdimethyl diallyl malonate. Kinetic profile based on H (MIVIR, and proposed reaction mechanism.

Table 7 Asymmetric cyclization/hydrosilylation of dimethyl diallyl malonate catalyzed by palladium pyridine-oxazoline complexes...

We shall consider reactions catalysed by two different types of pro-catalyst the first (type A) employs Pd-allyl cations ([Pd(a]lyl)(PCy3)]+/Et3SiH or [Pd(allyl)(MeCN)2] + ), and the second (type B) employs Pd-alkyl or chloro complexes ([(phen)Pd(Me)(MeCN)]+, where phen = phenanthroline, and [(RCN)2PdCl2]). These two types of catalysts give very different products in the cyclo-isomerisation of typical 1,6-dienes such as the diallyl-malonates (10), Scheme 12.6. Since there is known to be a clear order of thermodynamic stability 11 < 12 <13, with a difference of ca. 3-4 kcal mol 1 between successive pairs, any isomerisation of products under the reaction conditions will tend towards production of 12 and 13 from 11 and 13 from 12. Clearly, when 11 is the major product (as with pro-catalysts of type A), it must be the kinetic product (see Chapter 2 for a discussion of kinetic and thermodynamic control of product distributions). However, when 12 is generated selectively, as it is with pro-catalysts of type B, there is the possibility that this is either generated by rapid (and selective) isomerisation of 11 or generated directly from 10. 

The Pd enolates also undergo the intramolecular Michael addition when the allyl / -keto carboxylate or diallyl malonate 450, in which an enone is present at a suitable position, is treated with Pd(0) catalyst [190], The main product is the saturated ketone 451, and the allylated product 452 is obtained as a byproduct. 

Groups 10-12. Proton NMR was used to characterise an intermediate r -allyl coordinated pincer complex in the palladium-catalysed allylation of aldehydes and imines.1155 Low-temperature 111 and 13C NMR spectra, and H NOESY data established the mechanism for palladium-catalysed cyclisation/ hydrosilylation of dimethyl diallyl malonate, via (234, E = C02Me).1156 High-pressure 31P 1H NMR studies on coploymerisation of styrene with CO, catalysed by a Pd( 11)-(/L.V-BINAPHOS) complex, gave evidence for a number of active complex intermediates.1157... 

Further modification in snpport of the ruthenium carbene complex with ionic liquid media was described by Wakamatsu et al. [54]. The RCM of diethyl diallyl-malonate using a new catalyst was carried out under an argon atmosphere in the presence of 5 mol% catalyst in CHjClj/[bmim]BF (9 1) at room temperature. The starting material was consumed after 0.5 h to provide a product with 94% yield (Scheme 17.8). Continuous fast conversion was observed, and reliable reusability was realized by the fifth cycle. 

Diallyl malonate esters containing an a-aryl substituent (critical ) undergo decarboxylation to give the allyl 4-pentenoates. ° 2,3-Alkadienyl 2-alkynoates also decarboxylate, but during the reunion the aUenyl and alkynyl fragments are transposed. ... 

The sulfonylation of alkyl radicals plays an important role in the copolymerization of olefins with sulfur dioxide [53a]. In a recent study, Shevlin [53b] has shown that the cyclooligomerization of diallyl malonate could be controlled by the addition of a chain transfer agent such as PhSH (Eq. 22). 

Not only allyl j6-keto esters, but also the diallyl malonate derivative 580 underwent decaboxylation-allylation to give allyl o -allylcarboxylate 581. The nitro ester 582 is very reactive and the allylation proceeded even at —50 °C to give the a-allylnitroalkane 583 [209]. 

Hydrolysis of the dialkylated jS-keto esters and malonates is not easy, and usually harsh conditions are required. Also decarboxylation occurs only at high temperature. On the other hand, hydrolysis and decarboxylation reactions of substituted allyl -keto esters and allyl malonates using Et3N-HC02H proceed at room temperature under neutral conditions. THP-protected allyl jS-keto ester 597 was converted to 598 at room temperature without deprotection of THP [213]. The free mono-carboxylic acid 600 was obtained smoothly from the disubstituted diallyl malonate 599 [214]. 

Scheme 7. RCM of diethyl-diallyl-malonate to give the diethyl ester of 3-cyclopentene-l,l-dicarboxylic acid.

When hydroxyl radicals are generated in the flow cell in the presence of diallyl-malonic acid (R = H in 5-1), the ESR spectrum shown in Fig. 35 was recorded, which consists of a doublet of triplets the hyperfine splitting constants for the doublet and the triplets are 22.0 and 24.5 G, respectively. This multiplicity requires that the radical formed has a structure in which the unpaired electron interacts with three protons, two of which are equivalent. Of the following possible species (5-lV, -V, -VI, -VII, and -VIII), which can be formed initially, only two (3-V and -VII) fulfil this requirement. 

---