Formation of tungsten ethylidene complexes from diethyl complexes through a proton-catalyzed rearrangement of ethylene.

W(NAr)2Et2 (Ar = 2,6-diisopropylphenyl) reacts with two equivalents of RF9OH (ORF9 = OC(CF3)3) to yield W(NAr)(ArNH2)(ORF9)2(C2H4) complexes and ethane. In solution W(NAr)(ArNH2)(ORF9)2(C2H4) decomposes to give RF9OH, ethane, W(NAr)(ORF9)2(C2H4), and W(NAr)(NHAr')(ArNH2)(ORF9), in which Ar' contains a dehydrogenated isopropyl group (Ar' = (2-i-Pr)(6-CMe[double bond, length as m-dash]CH2)C6H3) coordinated to the metal. On a similar time scale W(NAr)(ORF9)2(CHCH3) complexes are formed from W(NAr)(ORF9)2(C2H4) through an ArNH2-catalyzed rearrangement of the ethylene ligand. W(NAr)(NHAr')(ArNH2)(ORF9) reacts with cyclohexene to form methylenecyclohexene and complexes that contain an NHAr″ ligand where Ar″ is a disubstituted (methyl/aryl) alkylidene, (2-i-Pr)(6-CMe)C6H3) that is tethered to the metal through the amido nitrogen. In contrast to W(NAr)(ArNH2)(ORF9)2(C2H4), analogous ORF6 (OCMe(CF3)2) and ORF3 (OCMe2(CF3)) complexes are relatively stable at 22 °C.