Stereodynamic tetrahydrobiisoindole “NU-BIPHEP(O)”s: functionalization, rotational barriers and non-covalent interactions

• Golo Storch,
• Sebastian Pallmann,
• Frank Rominger and
• Oliver Trapp

Beilstein J. Org. Chem. 2016, 12, 1453–1458, doi:10.3762/bjoc.12.141

• preparation of tailor-made functionalized stereodynamic ligands possible and give an outline for possible applications in enantioselective catalysis. Keywords: atropisomer; enantioselective DHPLC; ligand design; non-covalent interactions; Okamoto phases; phosphine ligand; stereodynamic ligands; Introduction

• method does not fulfil the requirements for a reliable rapid screening of novel stereodynamic ligands due to harsh conditions such as isotope exchange. We recently reported the rotational barriers of 3,3’ and 5,5’ substituted BIPHEP and BIPHEP(O) compounds based on enantioselective DHPLC by evaluation of

• CDCl3 resulted in significant signal splitting of Δδ = 0.30 ppm (31P{1H} NMR). This effect could be intensified by adding n-pentane which increased the splitting to Δδ = 0.41 ppm although signal broadening rose simultaneously (Figure 3B). Determination of rotational barriers by enantioselective DHPLC To