Unprecedented stereoselective synthesis of catalytically active chiral Mo3CuS4 clusters
Unprecedented stereoselective synthesis of catalytically active chiral Mo3CuS4 clusters
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DOI：
10.1002/chem.200500907
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发表时间：
2006-02-01
影响因子：
4.3
通讯作者：
Barberis, M
中科院分区：
文献类型：
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作者：
Feliz, M;Guillamón, E;Barberis, M
手性膦（+）-1，2-双[（2 R，5 R）-2，5-二氧杂环丁烷]对{Mo 3S 7 Cl 4}（n）聚合相的簇切除（二甲基磷杂环戊烷-1-基）]乙烷（（R，R）-Me-BPE）或与其对映体（（S，S）-Me-BPE）反应，立体选择性地形成三核簇合物[Mo 3S 4 {（R，R）-Me-BPE}（3）Cl-3]（+）（[（P）-1]（+））和[Mo3S4{（S，S）-Me-BPE}（3）Cl-3]（+）（[（M）-1]（+））。这些配合物具有不完全的立方体结构，金属原子限定了一个等边三角形和一个封端和三个桥接硫原子。P和M符号表示氯原子围绕C-3轴旋转，其中帽硫原子指向观察者。将铜掺入这些三核配合物中分别得到式[Mo 3 CuS 4 {（R，R）-Me-BPE}（3）Cl-4]（+）（[（P）-2]（+））或[Mo 3 CuS 4 {（S，S）-Me-BPE}（3）Cl-4]（+）（[（M）-2]（+））的异二金属立方烷型化合物，其中三核前体的手性在最终产物中得以保留。阳离子配合物[（P）-1]（+）、[（M）-1]（+）、[（P）-2]（+）和[（M）-2]（+）联合收割机将金属簇骨架的手性与光学活性二膦配体的手性结合。已知的外消旋[Mo 3CuS 4（dmpe）（3）Cl-4]（+）簇合物（dmpe= 1，2-双（二甲基膦基）乙烷）以及新的对映体纯的Mo 3 CuS 4 [（P）-2]（+）和[（M）-2]（+）配合物是1-重氮-5-己烯-2-酮（3）的分子内环丙烷化和烯烃如苯乙烯和2-苯基丙烯的分子间环丙烷化的有效催化剂，重氮乙酸乙酯。在所有情况下，以高产率获得环丙烷化产物。在烯烃的分子间环丙烷化中的非对映选择性和在分子间或分子内过程中的对映选择性仅是中等的。
Cluster excision of polymeric {Mo3S7Cl4}(n) phases with chiral phosphane (+)-1,2-bis[(2R,5R)-2,5-(dimethylphospholan-1-yl)] ethane ((R,R)-Me-BPE) or with its enantiomer ((S,S)-Me-BPE) yields the stereoselective formation of the trinuclear cluster complexes [Mo3S4{(R,R)-Me-BPE}(3)Cl-3](+) ([(P)-1](+)) and [Mo3S4{(S,S)-Me-BPE}(3)Cl-3](+) ([(M)-1](+)), respectively. These complexes posses an incomplete cuboidal structure with the metal atoms defining an equilateral triangle and one capping and three bridging sulfur atoms. The P and M symbols refer to the rotation of the chlorine atoms around the C-3 axis, with the capping sulphur atom pointing towards the viewer. Incorporation of copper into these trinuclear complexes affords heterodimetallic cubane-type compounds of formula [Mo3CuS4{(R,R)-Me-BPE}(3)Cl-4](+) ([(P)-2](+)) or [Mo3CuS4{(S,S)-Me-BPE}(3)Cl-4](+) ([(M)-2](+)), respectively, for which the chirality of the trinuclear precursor is preserved in the final product. Cationic complexes [(P)-1](+), [(M)-1](+), [(P)-2](+), and [(M)-2](+) combine the chirality of the metal cluster framework with that of the optically active diphosphane ligands. The known racemic [Mo3CuS4(dmpe)(3)Cl-4](+) cluster (dmpe=1,2-bis(dimethylphosphanyl)ethane) as well as the new enantiomerically pure Mo3CuS4 [(P)-2](+) and [(M)-2](+) complexes are efficient catalysts for the intramolecular cyclopropanation of 1-diazo-5-hexen-2-one (3) and for the intermolecular cyclopropanation of alkenes, such as styrene and 2-phenylpropene, with ethyl diazoacetate. In all cases, the cyclopropanation products were obtained in high yields. The diastereoselectivity in the intermolecular cyclopropanation of the alkenes and the enantioselectivity in the inter- or intramolecular processes are only moderate.