SonnebornBergermethoden

Sonneborn-Bergemethoden, or Sonneborn–Berger methods, refer to a group of classical analytical techniques in organic chemistry used to help determine the absolute configuration of chiral centers, particularly in secondary alcohols and related compounds. The methods are named after researchers credited with developing early approaches in stereochemical analysis and were widely used before modern spectroscopic and crystallographic methods became routine.

The core idea of the Sonneborn–Berger approach is to transform a chiral molecule into derivatives or diastereomeric adducts that exhibit predictable and distinguishable spectroscopic signatures. By comparing the behavior of these derivatives—such as optical rotation, infrared or NMR signals, or other chiroptical properties—with reference data, researchers can assign the configuration of the original center. In practice, the methods rely on forming diastereomers whose stereochemical relationships produce observable, interpretable differences.

Applications of the Sonneborn–Berger methods have included structural elucidation of natural products, alkaloids, and other complex organic molecules where direct crystallography is challenging. They provided a practical means of stereochemical assignment in the mid- to late 20th century and complemented other techniques available at the time.

Today, these methods are considered of historical importance. They have been largely superseded by single-crystal X-ray diffraction, advanced NMR with chiral solvating agents, and modern chiroptical methods, though they may still be referenced for educational context or specialized cases. See also absolute configuration, stereochemistry, and chiroptical spectroscopy.