(R)-4-(Alkylthiomethyl)-5,5-dimethyl-2-(2′-hydroxyphenyl)-2-oxazolines are demonstrated to be highly suitable chiral auxiliaries for the two-step conversion of the half-sandwich complex [Ru(η6-C6H6)(bpy)Cl]Cl, bpy = 2,2′-bipyridine, into Δ-configured ruthenium polypyridyl complexes. The tailored thioether substituent at the oxazoline ring is essential for this conversion and not only promotes the removal of the benzene moiety but also controls the absolute metal-centered configuration. Applied to osmium, this strategy resulted in the first highly asymmetric synthesis of Δ-[Os(bpy)3](PF6)2.
(R)-4-(烷
硫基甲基)-5,5-二甲基-2-(2'-羟基苯基)-2-
恶唑啉被证明是非常适合半夹心配合物[Ru]两步转化的手性助剂。 (η6-
C6H6)(bpy)Cl]Cl, bpy = 2,2′-联
吡啶,形成 Δ 构型
钌聚
吡啶配合物。
恶唑啉环上特制的
硫醚取代基对于这种转化至关重要,不仅促进苯部分的去除,而且控制绝对的
金属中心构型。应用于
锇时,该策略首次实现了 Δ-[Os(bpy)3](PF6)2 的高度不对称合成。