1.3- dipole metathesis

Trifluoromethyl-substitutedazimines are surprisingly stable compounds. They are accessible by 1,3-dipole metathesis from tnfluoromethyl-substituted azomethine imines and certain nitroso compounds [187, 188] On photolysis, an electrocyclic ring closure first gives the triaziridines, which are stable at room temperature. On heating above 80-100 C, a valence tautomenzation takes place and azimines are formed [189] (equation 43). 

By analogy to the alkene metathesis, this reaction sequence is called 1,3-dipol metathesis. 

Within this chapter, two sections are devoted to rhodium and ruthenium. The two main procedures using rhodium are first, the formation of 1,3-dipoles from diazocompounds followed by a 1,3-dipolar cycloaddition [10] and second, hy-droformylation [11], The ruthenium-catalyzed domino reactions are mostly based on metathesis [12], with the overwhelming use of Grubbs I and Grubbs 11 catalysts. 

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