Enantioselective π-Complexation. Synthesis of Enantiomerically Pure Planar Chiral Ruthenocenes
作者:Ulrich Koelle、Karin Bücken、Ulli Englert
DOI:10.1021/om950736i
日期:1996.3.5
Reaction of half-sandwich complexes Cp*RuL2ch, featuring a chiral auxiliary ligand L2ch, with prochiral cyclopentadienides Cppc- gave enantiomericallypure (>95% ee) or enriched ruthenocenes Cp*RuCppc 4. For the chiral auxiliary L2ch were tested a pyridyloxazoline (ref 15), the diolefin nopadiene (ref 16), and the amino acids methionine and proline, which form relatively labile complexes with the Ru(II)
半夹心的反应复合物的Cp * RUL 2 CH,设有手性辅助配位体L 2 CH,与前手性cyclopentadienides的Cp PC - ,得到对映体纯(> 95%ee)或非富集ruthenocenes的Cp * RuCp PC 4。对于手性助剂L 2 ch,测试了吡啶基恶唑啉(参考文献15),二烯烃Nopadiene(参考文献16)以及蛋氨酸和脯氨酸氨基酸,它们与Ru(II)片段Cp * Ru +形成了相对不稳定的络合物。对于前手性环戊二烯基Cp pc Li,1-叔丁基-3-甲基环戊二烯基,1-叔丁基的Li衍生物使用了丁基丁基茚基和1-叔丁基-3-苄基茚基。对映体过量的测定是通过衍生化富烯阳离子络合物[Cp pc RuC 5 Me 4 CH 2 ] +(5)的衍生化步骤完成的,在加入(S)-α-苯乙胺后,生成非对映异构体混合物Cp pc RuC 5 H 4 CH 2 NHCH(Me)Ph(6)。4c的绝对配置(Cp