Cyclic Compounds. Part I. Experiments on the Synthesis of Cyclopentane Derivatives Related to Wieland's Tricarboxylic Acid

\(\beta\)-Carboxypropionylcyclopentane (I: R=R'=H) has been synthesised by an extension of the Perkin ring-closure, applied to ethyl \(\beta\)-oxo-adipate² and 1,4-di-iodobutane and the constitution elucidated. A useful variation of the reaction, applied to ethyl 7-methyl-3-oxo-octanoate^3a,3b (V) and 1,4-di-iodobntane, provides a new route to the synthesis of 5-rnethylhexanoylcyclopentane (III: R=H).

A synthesis of 2-methyl-1-(\(\beta\)-carboxypropionyl) cyclopentane-2,3-dicarboxylic acid (VII: R=R₁=R₂=R₃ =H) is also described analogously.