TY - JOUR
T1 - Dioxomolybdenum(VI) complexes as catalysts for the hydrosilylation of aldehydes and ketones
AU - Reis, Patrícia M.
AU - Romão, Carlos C.
AU - Royo, Beatriz
PY - 2006
Y1 - 2006
N2 - The dioxomolybdenum(vi) complexes [MoO2Cl2] (1), [MoO2(acac)2] (2), [MoO2(S2CNEt 2)2] (3), [CpMoO2Cl] (4), [MoO 2(mes)2] (5) and the polymeric organotin-oxomolybdates [(R3Sn)2MoO4] [R = n-Bu (6), t-Bu (7), Me (8)] were examined as catalysts for the hydrosilylation of aldehydes and ketones with dimethylphenylsilane. Of these, [MoO2Cl2] (1) was the most efficient catalyst, affording quantitative yields of the corresponding silylated ethers at room temperature in acetonitrile. Complexes 2, 4-8 also catalyzed the same reaction but required heating at 80 °C and longer reaction times compared with 1. Compound 3 is inactive. The wide scope of molybdenum oxide-mediated hydrosilylation was established with a variety of aldehydes and ketones. Counter intuitively, the activity of 1 is highest in NCMe. In the absence of a carbonyl substrate, [MoO2Cl 2(NCBut)] (10) reacts with HSiMe2Ph affording [MoO(OSiMe2Ph)Cl2]2 (11) which has been fully characterized by NMR and IR spectroscopy, elemental analyses and mass spectrometry. Addition of radical scavengers strongly slows down the [MoO 2Cl2]-based hydrosilylation suggesting the intermediacy of oxygen-centered radicals.
AB - The dioxomolybdenum(vi) complexes [MoO2Cl2] (1), [MoO2(acac)2] (2), [MoO2(S2CNEt 2)2] (3), [CpMoO2Cl] (4), [MoO 2(mes)2] (5) and the polymeric organotin-oxomolybdates [(R3Sn)2MoO4] [R = n-Bu (6), t-Bu (7), Me (8)] were examined as catalysts for the hydrosilylation of aldehydes and ketones with dimethylphenylsilane. Of these, [MoO2Cl2] (1) was the most efficient catalyst, affording quantitative yields of the corresponding silylated ethers at room temperature in acetonitrile. Complexes 2, 4-8 also catalyzed the same reaction but required heating at 80 °C and longer reaction times compared with 1. Compound 3 is inactive. The wide scope of molybdenum oxide-mediated hydrosilylation was established with a variety of aldehydes and ketones. Counter intuitively, the activity of 1 is highest in NCMe. In the absence of a carbonyl substrate, [MoO2Cl 2(NCBut)] (10) reacts with HSiMe2Ph affording [MoO(OSiMe2Ph)Cl2]2 (11) which has been fully characterized by NMR and IR spectroscopy, elemental analyses and mass spectrometry. Addition of radical scavengers strongly slows down the [MoO 2Cl2]-based hydrosilylation suggesting the intermediacy of oxygen-centered radicals.
UR - http://www.scopus.com/inward/record.url?scp=33645505325&partnerID=8YFLogxK
U2 - 10.1039/b514930d
DO - 10.1039/b514930d
M3 - Article
C2 - 16585971
AN - SCOPUS:33645505325
VL - 6
SP - 1842
EP - 1846
JO - Dalton transactions (Cambridge, England : 2003)
JF - Dalton transactions (Cambridge, England : 2003)
SN - 1477-9234
IS - 15
ER -