Efficient asymmetry generation in the synthesis of oxo-rhenium(V) complex cis-[ReOCl2[OCMe2CMe2OP(OCMe2CMe2O)]py].
Efficient asymmetry generation in the synthesis of oxo-rhenium(V) complex cis-[ReOCl2[OCMe2CMe2OP(OCMe2CMe2O)]py].
复制标题
氧铼(V)络合物顺式-[ReOCl2[OCMe2CMe2OP(OCMe2CMe2O)]py]合成中有效产生不对称性。
DOI：
10.1002/anie.200219501
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发表时间：
2003
影响因子：
--
通讯作者：
T. Głowiak
中科院分区：
文献类型：
--
作者：
W. Rybak;A. Skarżyńska;T. Głowiak
立体化学最有趣的挑战之一是去外消旋化和制备纯手性化合物。[1]尽管在不对称有机合成方面取得了巨大的进展，但真正的无机化合物的“绝对”不对称制备只有几个例子，[2]这些也包括自发拆分过程。[3]因此，在圆偏振光[4a，B]或平行磁场[4c]中观察到[Cr（ox）3] 3-[x2 +]离子及其衍生物的部分光分辨。Gillard和他的同事已经描述了手性多硫化物（NH4）2 [Pt（S5）（S6）2]·2 H2O的合成。[5]该复合物自发结晶，其中一种对映体过量。它是由K2PtCl6和过量的（NH4）2Sn的充分搅拌的水反应混合物获得的，保持在pH 9.4。Kondepudi及其同事已经表明，虽然NaClO3从未搅拌的溶液中结晶产生外消旋的（N）-和（N）-NaClO3的聚集体（立方空间群P213），但剧烈搅拌会引发自发对称性破缺，并几乎只产生单手性晶体。[6]Asakura等人已经证明了在搅拌的悬浮液中通过手性自催化机制从光学非活性底物产生光学活性顺式-[CoBr（NH3）（en）2] Br2（en = 1，2-乙二胺）。[7]最近，据报道，NaClO3从反平行自旋电子照射的溶液中结晶，导致右旋晶体过量，而平行自旋正电子照射产生具有相反手性的晶体。[8]Keszthelyi和Szabó-Nagy已经描述了在多晶材料中发现的少量对映体过量，该对映体过量是在从具有（N）-和（N）-[Co（en）3] 3+或[Ir（en）3] 3+离子的（N）-和（N）-酒石酸盐（2R）的外消旋溶液中结晶时发现的。[9]后两篇文章的作者声称，观察到的部分去消旋化是由于电弱力。显然，这些准备工作只能在涉及物理场和/或自催化手性放大机制的非平衡条件下才能成功。然而，在过渡金属配合物的制备中，手性不对称性的产生和大量的光学产率仍然是相当罕见的。在我们研究螺膦HP（OCMe2CMe2O）2的配位能力的过程中，[10]我们合成了手性配合物cis-[ReOCl 2 {OCMe2CMe2OP-（OCMe2CMe2O）} py]（cis-1，py =吡啶）作为外消旋体。[10a]除了单齿配体外，六配位配合物还含有螯合亚磷酸酯二醇合（1H2O）配体，螺正膦（OCMe2CMe2O）POCMe2CMe2OH的去质子化互变异构形式。该复合物似乎是刚性的NMR时间尺度上。
One of the most intriguing challenges of stereochemistry is deracemization and the preparation of homochiral compounds.[1] Despite the great progress in asymmetric organic synthesis, there are only several instances of genuine “absolute” asymmetric preparation of inorganic compounds,[2] these include spontaneous resolution processes too.[3] Thus, a partial photoresolution either in circularly polarized light [4a, b] or a parallel magnetic field [4c] has been observed for the [Cr (ox) 3] 3À ion and its derivatives. Gillard and his associates have described the synthesis of the chiral polysulphide (NH4) 2 [Pt (S5)(S6) 2]· 2 H2O.[5] The complex crystallizes spontaneously with one enantiomer in excess. It was obtained from a well-stirred water reaction mixture of K2PtCl6 and an excess of (NH4) 2Sn, maintained at pH 9.4. Kondepudi and coworkers have shown that, whereas the crystallization of NaClO3 from unstirred solutions yields a racemic conglomerate of (þ)-and (À)-NaClO3 (cubic space group P213), vigorous stirring triggers spontaneous symmetry breaking and produces almost exclusively crystals of single handedness.[6] Asakura et al. have demonstrated the generation of optically active cis-[CoBr (NH3)(en) 2] Br2(en= 1, 2-ethanediamine) from optically inactive substrates in a stirred suspension by a chiral autocatalysis mechanism.[7] More recently, it has been reported that the crystallization of NaClO3 from a solution irradiated by antiparallel-spin electrons results in dextrorotatory crystals in excess, whereas irradiation by parallelspin positrons yields crystals with the opposite handedness.[8] Keszthelyi and Szabó-Nagy have described a small enantiomeric excess found in polycrystalline material upon crystallization from racemic solutions of (þ)-and (À)-tartrate (2À) with either (þ)-and (À)-[Co (en) 3] 3+ or [Ir (en) 3] 3+ ions.[9] The authors of the latter two works have claimed that the observed partial deracemization is because of electroweak forces. Clearly, these preparations could only be successful under nonequilibrium conditions involving physical fields and/or autocatalytic chirality-amplification mechanisms. Nevertheless, in the preparation of transition-metal complexes, the generation of chiral asymmetry with substantial optical yields still remains rather rare.In the course of our research on the coordination capability of the spirophosphorane HP (OCMe2CMe2O) 2,[10] we synthesized a chiral complex cis-[ReOCl2 {OCMe2CMe2OP-(OCMe2CMe2O)} py](cis-1, py= pyridine) as a racemate.[10a] In addition to monodentate ligands, the six-coordinate complex also contains a chelating phosphite diolato (1À) ligand, a deprotonated tautomeric form of the spirophosphorane (OCMe2CMe2O) POCMe2CMe2OH. The complex appeared to be rigid on the NMR time scale.