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Dioxo-molybdenum(VI) and -tungsten(VI) BINOL and alkoxide complexes: Synthesis and catalysis in sulfoxidation, olefin epoxidation and hydrosilylation of carbonyl groups |
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| Authors: | Andr Pontes da Costa Patrícia M Reis Carla Gamelas Carlos C Romo Beatriz Royo |
| Institution: | aInstituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Quinta do Marquês, EAN, Apt. 127, 2781-901 Oeiras, Portugal bEscola Superior de Tecnologia, Instituto Politécnico de Setúbal, 2910-761 Setúbal, Portugal |
| Abstract: | The reaction of MoO2(mes)2 with S-H2BINOL (mes = 2,4,6-Me3C6H2; H2BINOL = 1,1′-bi-2-naphthol) and (CF3)2MeCOH in THF yielded the novel dioxo-molybdenum(VI) complexes MoO2(S-BINOL)(THF)2 and MoO2OCMe(CF3)2]2(THF), respectively. Similar tungsten derivatives WO2(S-BINOL)(THF) and WO2OCMe(CF3)2]2(THF) have been prepared by the reaction of WO2Cl2(DME) with the corresponding lithium salts of BINOL and 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, respectively. Catalytic experiments have shown that MoO2(S-BINOL)(THF)2 is an active catalyst in the sulfoxidation of methyl phenyl sulfide and in the epoxidation of cis-cyclooctene with tert-butylhydroperoxide, under mild conditions. The BINOL complex was, however, not found to be enantioselective. In addition, the catalytic activity of the molybdenum species MoO2(S-BINOL)(THF)2 and MoO2OCMe(CF3)2]2(THF) in the hydrosilylation of carbonyl groups has been explored. |
| Keywords: | BINOL Alkoxides Molybdenum Tungsten Catalysis |
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