Download 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. ... Ring contraction of 2,5-diketopiperazines by TRAL-alkylation led us to the stereoselective synthesis of original pyrrolidine-2,4-diones, a novel series of promising molecules with moderate anti-proliferative activity on breast cancer cells. ... Ring contraction of 2,5-diketopiperazines by TRAL- ...