Ligating simple amino alcohol or amino ester monomers containing enantiotopic fluorine substituents to the C-terminus of a helical peptide places the fluorine atoms in diastereotopic environments, and gives two distinct and easily identifiable signals in the 19F NMR spectrum. In the case of a dynamically inverting helix built from achiral monomers, the chemical shift separation between the 19F signals provides a simple means of analysing the ratio of screw-sense conformers in the oligomer, in cases where an asymmetric bias leads to a screw-sense preference.
                                    将含有对映体
氟取代基的简单
氨基醇或
氨基酯单体连接到螺旋肽的 C 端,将
氟原子置于非对映环境中,并在 19F NMR 光谱中产生两个不同且易于识别的信号。对于由非手性单体构建的动态反转螺旋,19F 信号之间的
化学位移分离提供了一种简单的方法,在不对称偏置导致螺旋顺应性偏好的情况下,可以分析低聚物中螺旋顺应性构象的比例。