Cinnamic acid, alkylation with preparation

In the laboratory of D. Ma, the asymmetric synthesis of several metabotropic glutamate receptor antagonists derived from a-alkylated phenylglycines was undertaken. The preparation of (S)-1-aminoindan-1,5-dicarboxylic acid (AIDA) started with the Perkin reaction of 3-bromobenzaldehyde and malonic acid. The resulting ( )-cinnamic acid derivative was hydrogenated and the following intramolecular Friedel-Crafts acylation afforded the corresponding indanone, which was then converted to (S)-AIDA. 

Acid fragment 3 was rapidly prepared by 1,3 dipolar cycloaddition of the requisite cinnamate 17 with tert-butyl azomethine ylide 16. However, the synthesis of the azomethine ylide 15 required rather harsh conditions in the alkylation step and suffered low yield in the methoxymethylation due to its inherent instability. This provided a racemic mixture of 3,4-tranY-disubstimted pyrrolidine... 

The cationic cyclization of polyisoprene with acid catalysts is well documented. The same reaction in polybutadienes requires much more severe conditions, higher temperatures and more acidic catalysts, and until recently has received much less attention. A cyclized polymer with a reduction of 35—40% of the initial unsaturation, can be prepared by treating cis-l,4-polybutadiene with an alkyl aluminium chloride-organic halide catalyst in xylene solution at >100 C."- Such polymers, containing polycyclic sequences apparently at random within the chains, have better skid resistance and tensile properties than the parent polymer. Cyclization has been reported to accompany other reactions in polydienes, for example the radiation-induced addition of carbon tetrachloride to 1,2-polybutadiene, and the direct addition of a o j unsaturated carboxylic acids (acrylic and cinnamic) to polydienes and polypentenamers. It is reported that the thermal isomerization of cis-transoidal poly(phenylacetylene) is accompanied by cyclization, and additionally chain scission and aromatization at temperatures >120°C. ... 

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