Multigram‐Scale Kinetic Resolution of 4‐Acetyl[2.2]Paracyclophane <i>via</i> Ru‐Catalyzed Enantioselective Hydrogenation: Accessing [2.2]Paracyclophanes with Planar and Central Chirality

Abstract

Abstract [2.2]Paracyclophane (PCP) derivatives have been promising platforms to study the element of planar chirality and through‐space electronic communications in π‐stacked molecular systems. To access enantiomerically pure derivatives thereof, a kinetic resolution of 4‐acetyl[2.2]‐PCP employing a ruthenium‐catalyzed enantioselective hydrogenation process was developed. This method can be performed on a multigram‐scale and gives access to enantiomerically pure derivatives with planar and central chirality of ( R p )‐4‐acetyl‐PCP (≥97% ee , 43%) and ( S p, S )‐PCP derivatives (≥97% ee , 46%), which are useful intermediates for the synthesis of sterically demanding PCP‐based ligand/catalyst systems and chiral synthons for engineering cyclophane‐based chiroptical materials. magnified image