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.
