Wolfgang Braun

Investigations into the hydrogenation of diolefins and prochiral olefins employing the “Daniphos”-type ligandsDedicated to the memory of Professor Noel McAuliffe.

A number of enantiopure, planar chiral diphosphines of the Daniphos-type have been synthesized in good chemical yields and excellent stereochemical outcome according to a modular, straightforward synthetic method based on an arene–chromium–tricarbonyl scaffold. They were readily converted to their rhodium complexes, two of which have been characterized by X-ray crystallography. Their catalytic performance has been assessed by carrying out hydrogenations of dienes and prochiral olefins, taking the Josiphos ligand as a reference system for comparison. Interesting influences of the substitution patterns and solvents were found. Reaction rates of the hydrogenations of diolefins were also found to be strongly dependent on the respective substituents.