The synthesis of three planar chiral pseudo-gem disubstituted [2.2]paracyclophane-derived P,N-pre-ligands is reported along with preliminary results of their activity in the amination of aryl bromides and chlorides. The pseudo-gem aminophosphines were capable of mediating the coupling reaction at a loading of 1 mol%.
Substituted planar chiral pyridyl[2.2]paracyclophanes were prepared by the palladium‐catalyzed desulfinative cross‐coupling of bromo[2.2]paracyclophanes and pyridine sulfinate salts. Pyridine‐substituted [2.2]paracyclophanes are useful building blocks in the preparation of catalysts, functionalized materials, and luminescent molecules. Yet the synthesis of many pyridine‐substituted [2.2]paracyclophanes is more challenging than expected due to the instability of traditional coupling partners. Pyridine sulfinates offer a solution to this shortcoming, permitting pyridyl[2.2]paracyclophanes to be prepared from readily available bromo[2.2]paracyclophanes. Our preliminary results indicate the potential of this chemistry. Amine, bromine and ester substituted planar chiral pyridines that are hard to synthesize by other methods were formed but formation of (bis)pyridines is still problematic.
Racemic bromo[2.2]paracyclophanes are directly transformed into enantiomerically pure planar chiral oxazolines in one step with simultaneous resolution of planar chirality.
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