Olefin Epoxidation Catalyzed by cis‐Dioxdomolybdenum(VI) Complexes Containing Chiral Alkoxo‐Imino Ligands Derived from (+)‐α‐Pinene

摘要: New chiral cis-dioxidomolybdenum compounds [MoO2(acac)(RN,O)] [R = Bn (1), pic (2)] and [{MoO2(acac)}2{μ-(O,N,N,O)}] (3) have been synthesized by treating [MoO2(acac)2] withthe corresponding enantiomerically pure alcohol-iminocompounds derived from (+)-α-pinene modification, (RN,OH) (R Bn, pic) (HO,N,N,OH), respectively. Compound [MoO2Cl2(O,N,N,O)] (4) has also prepared. All the were fully characterized both in solution solid state, including single-crystal X-ray diffraction analysis of 3. DFT studies support stereoselectivity synthesis compound Catalytic olefin epoxidation performed with cis-cyclooctene, (R)-limonene, trans-β-methylstyrene using derivatives 1–4 as catalyst precursors tert-butyl hydroperoxide (TBHP) or H2O2 oxidant. catalytic systems showed high chemoselectivity irrespective terminal oxidant used. The molybdenum exhibited medium to activity at mild reaction temperatures, but no substantial optical induction was observed. This study represents first use monoacetylacetonato-cis-dioxidomolybdenum homogeneous catalysts.