Tartrate-Derived Cyclopentadienes for the Synthesis of Chiral Substituted (<i>η</i><sup>5</sup>-Cyclopentadiene)(<i>η</i><sup>4</sup>-cycloocta-1,5-diene)cobalt(I) Complexes
tetrasubstituted cyclopentadiene 2, are obtained. The corresponding (η5-cyclopentadiene)(η4-cycloocta-1,5-diene)cobalt(I) complexes 3 and 4 are prepared through the deprotonation of the ligands with lithium diisopropylamide followed by the metathetic reaction of the lithium salts with tris(triphenylphosphine)cobalt(I) chloride and 1,5-cyclooctadiene. The complexes are isolated in an enantiomerically pure
获得了两个手性酒石酸酯衍生的配体,即二取代的环戊二烯1和新的四取代的环戊二烯2。相应的(η 5环戊二烯)(η 4 -cycloocta -1,5-二烯)合钴(I)络合物3和4是通过随后用三锂盐的复分解反应中与二异丙基氨基锂的配位体的去质子化制备(三苯基膦)氯化钴(I)和1,5-环辛二烯。在氩气下用干燥的二氧化硅色谱分离后,以对映体纯的状态分离复合物。2 − 4的结构已经通过单晶X射线衍射法测定。根据1 H和13 C NMR光谱讨论了配合物3和4在溶液中的动力学行为。
Chiral cyclopentadiene-mediated approach to enantioselective heterobimetallic Pauson–Khand reactions
作者:Ramon Rios、Sergi Paredes、Miquel A. Pericàs、Albert Moyano
DOI:10.1016/j.jorganchem.2004.09.046
日期:2005.1
When the dicobalt(hexacarbonyl) complex of N-(2-butynoyl)-4,4-dimethyloxazolidinone (1) is treated with chiral cyclopentadienyl (tricarbonyl)molybdenum anions, pairs of diastereomeric heterobimetallic (Co–Mo) complexes are obtained. In one instance, the two diastereomers have been separated by chromatography and they have been reacted with norbornadiene; each diastereomer leads with virtually complete