Efficient highly stereoselective synthesis of olefinic macrocyclic crown-formazans with the Z-configuration via ring-closure metathesis

RCM of 1,5-bis-o-allyloxyphenylformazans with the suitably located 1,ω-dienes leads to an efficient, highly stereoselective, synthetic approach towards Z-olefinic 15-membered ring macrocyclic crown-formazans with potential applications. A novel reduction of pyridine N-oxides to pyridines by the action of Grubbs’ catalyst has been discovered.