定义Definition
绝对构型是手性分子中原子在空间的真实排列，常用 CIP 规则的 R/S 描述符表示，与仅相对于参照化合物的“相对构型”相区别。
Absolute configuration is the actual spatial arrangement of atoms in a chiral molecule, usually expressed with CIP R/S descriptors, as distinct from relative configuration referenced to another compound.
确定方法Determination
单晶 X 射线衍射的反常散射（含重原子时最可靠）；与已知绝对构型的化合物化学关联；振动圆二色（VCD）或电子圆二色（ECD）与量子化学计算对比；手性衍生化试剂 NMR（莫舍尔法）。
Anomalous X-ray scattering on single crystals (best with heavy atoms); chemical correlation with compounds of known configuration; VCD or ECD compared with quantum calculations; NMR with chiral derivatising agents (Mosher’s method).
历史History
费歇尔（1891）任意指定（+）-甘油醛为 D 构型，糖类的相对构型都与之关联；1951 年比约特用 X 射线反常散射测定酒石酸铷钠的绝对构型，证实费歇尔的猜测恰好正确。
Fischer (1891) arbitrarily assigned (+)-glyceraldehyde the D configuration, relating all sugars to it; in 1951 Bijvoet determined the absolute configuration of sodium rubidium tartrate by anomalous X-ray scattering, showing Fischer’s guess was correct.
注意Caveats
R/S 是命名约定，与旋光方向（+/−）和 D/L 构型都没有必然对应；同一分子取代基改变后 R/S 可能改变而空间排列不变。
R/S is a naming convention unrelated to the sign of rotation or to D/L; changing a substituent can flip R/S without changing the spatial arrangement.
年表Timeline
- 1891
费歇尔约定甘油醛构型
Fischer’s glyceraldehyde convention
- 1951
比约特测定绝对构型
Bijvoet determines absolute configuration
- 1956
CIP R/S 体系
CIP R/S system