Related Experiment Video
Updated: May 15, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
The stereodynamics of 5,5'-disubstituted BIPHEPs
1Ruprecht-Karls-Universität Heidelberg, Organisch-Chemisches Institut, Heidelberg, Germany.
Abstract:
We investigated the stereodynamics of 5,5'-substituted tropos BIPHEP ligands (2,2'-bis(diphenylphosphino)-biphenyls) by enantioselective dynamic high-performance liquid chromatography (DHPLC) to elucidate the influence of the substitution pattern and electronics of the substituents (methyl, methoxy, and hydroxyl groups). By temperature-dependent dynamic HPLC measurements the activation parameters ΔG(╪), ΔH(╪), and ΔS(╪) could be determined with high precision, revealing that the activation barrier of these 5,5'-substituted BIPHEP ligands ranges in a narrow band between 87.8 and 93.0 kJ mol(-1), making them highly attractive as deracemizable dynamic chiral ligands in asymmetric catalysis. Interestingly, the activation parameters are highly influenced by a hydroxyl or methoxy group in the 5,5'-position of the BIPHEP ligands.
Related Concept Videos
Prochirality
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Directing and Steric Effects in Disubstituted Benzene Derivatives
Stereoisomerism of Cyclic Compounds
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement

