Ziegler s synthetic method, which included running reactions at high dilution to favor the intramolecular cyclization over competing intermolecular reactions, resulted in yields superior to those of existing procedures ( Laylin ) : he was able to prepare large-ringed alicyclic ketones, C 14 to C 33, in yields of 60 80 %.
22.
His work on medium-sized alicyclic and heterocyclic rings established him as a pioneer in stereochemistry and conformational theory and brought an invitation to give the first Centenary Lecture of the Chemical Society in London in 1949 . He synthesized medium-sized ring compounds with 8 to 12 members from dicraboxylic acid esters by acyloin condensation and explained their unusual chemical reactivity by a " nonclassical " strain because of energetically unfavorable conformations.
