New ruthenium complexes bearing chiral 1,2,4-triazol-5-ylidene ligands were obtained and tested in model asymmetric metathesis reactions. Low enantioselectivity in asymmetric ring-closing metathesis (ARCM) and moderate enantioselectivity in asymmetric ring-opening/ring-closing metathesis (AROCM) was observed.

A formal synthesis of Thienamycin from ethyl (E)–crotonate and a cyclic five-membered nitrone derived from 2-deoxy-d-ribose is described. The synthesis involves 1,3-dipolar cycloaddition, cleavage of the N–O bond in the adduct, and intramolecular N-acylation to afford a bicyclic carbapenam skeleton. Subsequent transformations of the five-membered ring substituents provide the title compound.