Cyclopropane-1,2-dicarboxylic esters, synthesis

Treatment of diethyl malonate and related compounds with 1,2-dihaloethane in the presence of base constitutes a classical method of cyclopropane synthesis296"300. The reaction can be conveniently carried out under PTC conditions. An improved method utilizing solid-liquid phase transfer catalysis has been reported298. The reaction of dimethyl or diethyl malonate with 1,2-dibromoalkanes except for 1,2-dibromethane tends to give only low yields of 2-alkylcyclopropane-l, 1-dicarboxylic esters. By the use of di-tm-butyl malonate, their preparations in satisfactory yields are realized (equation 134)297. The 2-alkylcyclopropane derivatives are also obtained from the reaction of dimethyl malonate and cyclic sulfates derived from alkane-1,2-diols (equation 135)301. Asymmetric synthesis... 

Substitution of a cyclopropane by two geminal electron-withdrawing groups makes the three-membered ring very susceptible to nucleophilic attack. The readily-prepared phosphonium salt (480) condenses with the p-keto-ester anion (479) to furnish the cyclopentene (481). Similar nucleophilic attack on cyclopropane-l,l-dicarboxylic ester derivatives has been adapted to the synthesis of several prostaglandins. ... 

Imamoto et al. have reported a samarium(II) iodide promoted reductive ring opening of cyclopropane-1,1-dicarboxylie esters for the synthesis of 8-lactones [121] (Scheme 74). Treatment of various cyclopropane-1,1-dicarboxylate esters 328 with a variety of ketones 329 in the presence of samarium iodide and a catalytic amount of tris(dibenzoylmethiodo)iron(III) gave a diverse array of 2-methoxycarbonyl-5,5-disubstituted 8-lactone 330 in good yields. The use of a catalytic amount of the iron complex was imperative to accelerate the reductive ring opening of the cyclopropane. 

This version of the Curtius rearrangement has been applied to the synthesis of amino acid analogs and structures containing amino acids. Several m-2-aminocyclopropane carboxylate esters were prepared by selective hydrolysis of cyclopropane-1,2-dicarboxylates, followed by reaction with DPPA.267... 

In a synthesis of optically active 11-deoxy-PGEi, Abraham [141] prepared the cyclopropane derivative (133) by ozonolysis of the methyl ester of (-)-2-vinylcyclopropane-l,l-dicarboxylic acid and elaboration of the resulting aldehyde, and then effected a condensation with trimethyl heptane-1,1,7-tri-carboxylate to give, after hydrolysis, the cyclopentanone (134) which afforded 1 l-deoxy-PGE and its C-IS epimers on alkali treatment. 

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