Versatile Reactivity of Scorpionate‐Anchored YttriumDialkyl Complexes towards Unsaturated Substrates

A series of unusual chemical‐bond transformations were observed in the reactions of high active yttriumdialkyl complexes with unsaturated small molecules. The reaction of scorpionate‐anchored yttriumdibenzyl complex [Tp Me2 Y(CH 2 Ph) 2 (thf)] ( 1 , Tp Me2 =tri(3,5‐dimethylpyrazolyl)borate) with phenyl isothiocyanate led to CS bond cleavage to give a cubane‐type yttrium–sulfur cluster, {Tp Me2 Y(μ 3 ‐S)} 4 ( 2 ), accompanied by the elimination of PhNC(CH 2 Ph) 2 . However, compound 1 reacted with phenyl isocyanate to afford a C(sp 3 )H activation product, [Tp Me2 Y(thf){μ‐η 1 :η 3 ‐OC( CH Ph)NPh}{μ‐η 3 :η 2 ‐OC( CH Ph)NPh}YTp Me2 ] ( 3 ). Moreover, compound 1 reacted with phenylacetonitrile at room temperature to produce γ‐deprotonation product [(Tp Me2 ) 2 Y] + [Tp Me2 Y(N=CCHPh) 3 ] − ( 6 ), in which the newly formed NCCHPh ligands bound to the metal through the terminal nitrogen atoms. When this reaction was carried out in toluene at 120 °C, it gave a tandem γ‐deprotonation/insertion/partial‐Tp Me2 ‐degradation product, [(Tp Me2 Y) 2 (μ‐Pz) 2 {μ‐η 1 :η 3 ‐NC(CH 2 Ph)C H Ph}] ( 7 , Pz=3,5‐dimethylpyrazolyl).