Enantiopure Ruthenocenes Cp*Ru(1,2‐C5H3R1R2) with a Planar Chiral Cyclopentadienyl Ligand and a Pentamethylcyclopentadienyl Spectator Ligand
Enantiopure Ruthenocenes Cp*Ru(1,2‐C5H3R1R2) with a Planar Chiral Cyclopentadienyl Ligand and a Pentamethylcyclopentadienyl Spectator Ligand
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DOI：
10.1002/ejic.200500686
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发表时间：
2005-12
影响因子：
2.3
通讯作者：
G. E. Herberich;U. Englert;T. Wirth
中科院分区：
文献类型：
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作者：
G. E. Herberich;U. Englert;T. Wirth
以1，3，5-三嗪、环戊二烯和吗啉为原料，用Kreutzberger合成法合成了6-(吗啉基)富烯(7a)(94%)。同样，用(S)-2-甲氧甲基吡咯烷(HSMP)合成了6-[(S)-2-甲氧甲基吡咯烷]类似物7b(62%)。NaBHEt3在甲苯中加成得到环戊二烯Na[C5H4CH2-N(C2H4)2O](8a)(83%)和Na(C5H4CH2-SMP)(8b)(90%)。以[Cp*RuCl4]4和8b为原料合成了Cp*Ru(C5H4CH2-SMP)(5)，产率84%。相应的亚甲基亚胺盐[Cp*Ru(C5H4CH=SMP)]PF6(9)是由[Cp*Ru(MeCN)3]PF6和7b合成的，在四氢呋喃中可由LiAlH4加成成5。5与LiSbu在Et2O/环己烷中的非对映选择性锂化合，然后用亲电试剂E-X猝灭，得到了以E=F、Cl、Br、I、Me、CD3、SiMe3、PPh2、Au(PPh3)为油的1，2-二取代配合物Cp*Ru(E-C5H3CH2-SMP)10a-I，对映体纯度为98%。在四氢呋喃中用MeI季铵盐化和LiAlH4还原裂解10a、b和f，得到手性化合物Cp*Ru(1-E-2-MeC5H3)14a(E=F)、14b(E=Cl)和14F(E=CD3)。络合物14a、b、f不再具有中心手性。12的晶体结构是10f的LII加合物，通过内参照SMP基团的(S)-立体化学给出了绝对构型。平面手性络合物14b的绝对构型是由14b晶体的反常X射线色散确定的。
Kreutzberger’s synthesis was used to produce 6-(morpholino)fulvene (7a) from 1,3,5-triazine, cyclopentadiene and morpholine (94 %). Likewise with (S)-2-(methoxymethyl)pyrrolidine (HSMP) the 6-[(S)-2-(methoxymethyl)pyrrolidino] analogue 7b was obtained (62 %). Hydride addition from NaBHEt3 in toluene afforded the cyclopentadienides Na[C5H4CH2–N(C2H4)2O] (8a) (83 %) and Na(C5H4CH2–SMP) (8b) (90 %). Cp*Ru(C5H4CH2–SMP) (5) was synthesized from [Cp*RuCl]4 and 8b (84 % yield). The related methyleneiminium salt [Cp*Ru(C5H4CH=SMP)]PF6 (9) was made from [Cp*Ru(MeCN)3]PF6 and 7b and could be transformed into 5 by hydride addition from LiAlH4 in THF. Diastereoselective lithiation of 5 with LisBu in Et2O/cyclohexane and subsequent quenching with electrophiles E–X gave enantiomerically pure (de > 98 %), 1,2-disubstituted complexes Cp*Ru(E–C5H3CH2–SMP) 10a–i with E = F, Cl, Br, I, Me, CD3, SiMe3, PPh2, Au(PPh3) as oils. The chiral auxiliary was removed from 10a, b, and f by quaternization with MeI and subsequent reductive cleavage with LiAlH4 in THF to afford the exclusively planar chiral complexes Cp*Ru(1-E-2-MeC5H3) 14a (E = F), 14b (E = Cl), and 14f (E = CD3). The complexes 14a,b,f no longer possess central chirality. The crystal structure of 12, a LiI adduct of 10f, gave the absolute configuration via internal reference to the (S)-stereochemistry of the SMP group. The absolute configuration of the planar chiral complex 14b was determined from the anomalous X-ray dispersion of the crystals of 14b.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)