Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Construction of the left segment of azadirachtin in naturally occurring enantiomer is described. The key reaction is an intramolecular Diels-Alder reaction, which was performed under thermal conditions to afford the highly functionalized decalin compounds selectively.