Highly Z- and enantioselective ring-opening/cross-metathesis reactions and Z-selective ring-opening metathesis polymerization

Stopping the gap: A notable shortcoming in olefin metathesis chemistry was the lack of methods for the selective synthesis of Z alkenes. A breakthrough has now been achieved by the employment of a new type of chiral Mo complex (see scheme; TBS=tert-butyldimethylsilyl, X=Cl, Br, I). The first examples of the titled reactions are discussed.