transmission/amplification system triggered by chiral recognition, we synthesized a series of zincbilinone (ZnBL) trimers bearing a tripodal spacer and investigated homohelicity induction by complexation with chiral α-amino esters. Controlling the length of the peripheral alkyl groups in ZnBL moieties led to preorganization of the trimer to homohelical conformers. In addition, complexation with chiral α-amino
A series of zincbilinone derivatives bearing a chiral auxiliary at the helix terminal were prepared to investigate the helical chirality induction in the bilinone framework by the point chirality of the chiral auxiliary. Chiral induction was sensitive to the distance to the asymmetric carbon as well as to substituents on the asymmetric carbon. When the chiral carbon was directly attached to the bilinone
制备了一系列在螺旋末端带有手性助剂的锌胆酮衍生物,以研究手性助剂的点手性对胆酮骨架中螺旋手性的诱导。手性诱导对与不对称碳的距离以及对不对称碳上的取代基敏感。当手性碳直接连接到胆酮 19-氧并带有芳香基团时,在 [19-烷氧基-2,7,13,18-四甲基-3,8,12,17-变温 1H NMR 和 CD 研究证明了四乙基-1-胆酮基]锌(II)。(R)-2-甲基-1-苯基丙氧基在 CD2Cl2 中 223 K 时以 >95% 的对映体过量诱导 P-螺旋(ΔΔG° ≥ 6.8 kJ/mol)。
Homohelicity-enriched zinc bilinone dimers with chiral aliphatic spacers. Synthesis and application to chiral induction of a nematic liquid crystal
The zincbilinone (ZnBL) dimers 4 and 5 bearing chiral aliphatic spacers ((2S,4S)-2,4-pentanedioxy and (3S,5S)-2,6-dimethyl-3,5-heptanedioxy for 4 and 5, respectively) were newly prepared, and their conformational distribution was investigated. The 1H NMR and circular dichroism spectra revealed that the present dimers predominantly adopted the homohelicity conformation (MM and PP for 4 and 5, respectively)
锌bilinone(ZnBL)二聚体4和5的轴承手性脂肪族间隔物((2小号,4小号)-2,4- pentanedioxy和(3小号,5小号)-2,6-二甲基-3,5- heptanedioxy为4和5分别)是新制备的,并对其构象分布进行了研究。的1 H NMR和圆二色性光谱显示本二聚体主要采用的构象homohelicity(MM和PP为4和5),尽管具有相应亚基结构的参考单体显示出较差的螺旋度富集。还研究了这些ZnBL二聚体对向列液晶(N-(4-甲氧基亚苄基)-4-丁基苯胺,MBBA)的螺旋扭曲能力。通过将二聚体掺入MBBA,可以实现高效的手性向列诱导。特别地,二聚物5表现出β中号的1800微米值-1。