Departamento de Química Inorgánica, Orgánica y Bioquímica, Universidad de Castilla-La Mancha, Campus Universitario, 13071-Ciudad Real, Spain.
Inorg Chem. 2011 Mar 7;50(5):1826-39. doi: 10.1021/ic102242x. Epub 2011 Jan 11.
New enantiopure imines (1-9) with a chiral substrate to control the stereochemistry of a newly created stereogenic center have been synthesized by reaction of the commercially available (1R)-(-)-myrtenal and different primary amines. The diastereomerically enriched lithium-scorpionate compounds [Li(κ(3)-mobpza)(THF)] (10) (mobpza = N-p-methylphenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide), [Li(κ(3)-mobpza)(THF)] (11) (mobpza = N-p-methoxyphenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide), [Li(κ(3)-fbpza)(THF)] (12) (fbpza = N-p-fluorophenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide), and [Li(κ(3)-clbpza)(THF)] (13) (clbpza = N-p-chlorophenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide) were obtained by a diastereoselective 1,2-addition of an organolithium reagent to imines in good yield and with good diastereomeric excess (ca. 80%). The complexes [LiCl(κ(2)-R,R-fbpzaH)(THF)] (14) and [LiCl(κ(2)-R,R-clbpzaH)(THF)] (15) were obtained in enantiomerically pure form by the treatment of THF solutions of 12 or 13 with NH(4)Cl. The enantiomerically pure amines (R,R-mbpzaH) (16), (R,R-mobpzaH) (17), (R,R-fbpzaH) (18), and (R,R-clbpzaH) (19) were obtained by hydrolysis of the lithium-scorpionate compounds 10-13 with H(2)O. The lithium compound 12 was reacted with [TiCl(4)(THF)(2)] or [ZrCl(4)] to give the enantiopure complexes [MCl(3)(κ(3)-R,R-fbpza)] [M = Ti (20), Zr (21)]. The amine compound 18 reacted with [MX(4)] (M = Ti, X = O(i)Pr, OEt; M = Zr; X = NMe(2)) to give the complexes [MX(3)(κ(3)-R,R-fbpza)] (22-24). The reaction of Me(3)SiCl with [Zr(NMe(2))(3)(κ(3)-R,R-fbpza)] (24) in different molar ratios led to the halide-amide-containing complexes [ZrCl(NMe(2))(2)(κ(3)-R,R-fbpza)] (25) and [ZrCl(2)(NMe(2))(κ(3)-R,R-fbpza)] (26) and the halide complex 21. The isolation of only one of the three possible diastereoisomers of complexes 25 and 26 revealed that chiral induction from the ligand to the zirconium center took place. The structures of these compounds were elucidated by (1)H and (13)C{(1)H} NMR spectroscopy, and the X-ray crystal structures of 5, 12, 14, 15, and 24 were also established.
新的手性亚胺（1-9）具有手性底物，可以控制新形成的手性中心的立体化学，通过商业上可获得的（1R）-（-）-薄荷醇和不同的伯胺反应合成。立体选择性富集的锂-scorpionate 化合物[Li(κ(3)-mobpza)(THF)]（10）（mobpza = N-p-甲基苯基-（1R 和 1S）-1-[(1R)-6,6-二甲基双环[3.1.1]-2-庚烯-2-基]-2,2-双（3,5-二甲基吡唑-1-基）乙基酰胺）、[Li(κ(3)-mobpza)(THF)]（11）（mobpza = N-p-甲氧基苯基-（1R 和 1S）-1-[(1R)-6,6-二甲基双环[3.1.1]-2-庚烯-2-基]-2,2-双（3,5-二甲基吡唑-1-基）乙基酰胺）、[Li(κ(3)-fbpza)(THF)]（12）（fbpza = N-p-氟苯基-（1R 和 1S）-1-[(1R)-6,6-二甲基双环[3.1.1]-2-庚烯-2-基]-2,2-双（3,5-二甲基吡唑-1-基）乙基酰胺）和[Li(κ(3)-clbpza)(THF)]（13）（clbpza = N-p-氯苯基-（1R 和 1S）-1-[(1R)-6,6-二甲基双环[3.1.1]-2-庚烯-2-基]-2,2-双（3,5-二甲基吡唑-1-基）乙基酰胺）通过有机锂试剂对亚胺的立体选择性 1,2-加成以良好的产率和良好的非对映过量（约 80%）获得。配合物[LiCl(κ(2)-R,R-fbpzaH)(THF)]（14）和[LiCl(κ(2)-R,R-clbpzaH)(THF)]（15）通过 THF 溶液中 12 或 13 与 NH(4)Cl 的处理以手性纯形式获得。手性纯胺（R,R-mbpzaH）（16）、（R,R-mobpzaH）（17）、（R,R-fbpzaH）（18）和（R,R-clbpzaH）（19）通过 H(2)O 水解锂-scorpionate 化合物 10-13 获得。锂化合物 12 与[TiCl(4)(THF)(2)]或[ZrCl(4)]反应得到手性纯配合物[MCl(3)(κ(3)-R,R-fbpza)][M = Ti（20），Zr（21）]。胺化合物 18 与[MX(4)]（M = Ti，X = O(i)Pr，OEt；M = Zr；X = NMe(2)）反应得到配合物[MX(3)(κ(3)-R,R-fbpza)]（22-24）。Me(3)SiCl 与[Zr(NMe(2))(3)(κ(3)-R,R-fbpza)]（24）在不同的摩尔比下反应得到含有卤化物-酰胺的配合物[ZrCl(NMe(2))(2)(κ(3)-R,R-fbpza)]（25）和[ZrCl(2)(NMe(2))(κ(3)-R,R-fbpza)]（26）和卤化物配合物 21。只有两种可能的立体异构体 25 和 26 中的一种被分离出来，这表明手性诱导从配体到锆中心发生了。这些化合物的结构通过（1）H 和（13）C{(1)H}NMR 光谱阐明，并且 X 射线晶体结构的 5、12、14、15 和 24 也被建立。
