Design and Synthesis of a [2.2]Paracyclophane‐based Planar Chiral Dirhodium Catalyst and its Applications in Cyclopropanation Reaction of Vinylarenes with α‐Methyl‐α‐Diazo Esters

A planar chiral dirhodium paddlewheel complex Rh 2 ( S p −PCP) 4 based on the [2.2]paracyclophane has been synthesized for the challenging cyclopropanation of venylarene derivatives with tert ‐butyl α ‐diazo propionates. The homobimetallic rhodium catalyst relies on the high steric demand and rigidity of [2.2]paracyclophane that favors the cyclopropanation of 1‐aryl substituted, 1,1‐disubstituted and benzannulated alkenes over β ‐hydride migration at room temperature with high diastereoselectivity. magnified image