1,2-Selective Hydrosilylation of Conjugated Dienes
摘要:
Selective 1,2-hydrosilylation of 1,3-dienes is a challenging problem in transition metal catalysis. Butadiene, specifically, would be a useful substrate because 3-butenylsilane products have promise as superior coupling reagents for hybrid organic/inorganic materials synthesis. We report the first selective 1,2-hydrosilylation of conjugated dienes including butadiene. Hydrosilylation proceeds through a Pt(II/IV) cycle, and selectivity is generated at a hexacoordinate Pt(IV) complex that favors eta(2)-diene coordination and prevents pi-allyl complex formation.
The interaction of [MgCl2(THF)2] with [MoCl3O(THF)2] in 1:1 and 1:2 ratios in CH2Cl2 gave the paramagnetic complexes [(THF)3Mg(mu-Cl)3MoCl2O] I and [MoCl4 O(THF)}2Mg(THF)4].CH2Cl2 II (THF, tetrahydrofuran). In complex I, the molybdenum and magnesium atoms are octahedrally surrounded by three bridging chlorine atoms and terminal oxo-oxygen and two chlorine atoms and by three THF molecules, respectively. Complex II consists of Mg2+ ions coordinated by four THF molecules and two trans-[MoCl4O(THF)]- anions coordinated to an Mg atom by oxo O-atoms.
MgCl2 - one of the factors controlling the mechanism of the reaction between grignard reagents and titanium or zirconium tetrachloride. II