Bis S -4-isopropyloxazolin-2-yl pyridine rhodium Trichloride

Numerous highly enantioselective ring-forming reactions have also been discovered with the assistance of 1. Cyclopropanation with the rhodium complex of 1 furnishes rranr-cyclopropanes selectively (eq l)y A discrete ruthenium vinyl carbene was similarly successful in the stoichiometric cyclopropanation, whereas enantioselection in the copper(I)-catalyzed variant was nonselec- 

Both Diels-Alder and hetero-Diels-Alder reactions can be rendered stereoselective using l copper(II) salts, but inferior levels of stereoselection were observed relative to other pybox derivatives. Lanthanide-catalyzed 1,3-dipolar cycloaddition also exhibited moderate (61%) enantioselection.  

Lanthanide catalysis was again effective in ring-opening reactions of cyclic epoxides (eq 8). Finally, MAO-activated l-RuCL provides block copolymers of ethylene and hex-l-ene.  

Nishiyama, H. Shimada, T. Itoh, H. Sugiyama, H. Motoyama, Y., Chem. Commun. 1997, 1863. 

A list of General Abbreviations appears on the front Endpapers 

---