Addition of LiOHMT (OHMT = O-2,6-dimesitylphenoxide) to W(O)(CH-t-Bu)(PMe2Ph)2Cl2 led to WO(CH-t-Bu)Cl(OHMT)(PMe2Ph) (>4). Subsequent addition of Li(2,5-Me2C4H2N) to >4 yielded yellow W(O)(CH-t-Bu)(OHMT)(Me2Pyr)(PMe2Ph) (>5). Compound >5 is a highly effective catalyst for the Z-selective coupling of selected terminal olefins (at 0.2% loading) to give product in >75% yield with >99% Z configuration. Addition of two equivalents of B(C6F5)3 to >5 led to catalyst activated at the oxo ligand by B(C6F5)3. >5.B(C6F5)3 is a highly active catalyst that produces thermodynamic products (~20% Z).
展开▼
