Regioselective ortho-Palladation of [2.2]Paracyclophane Scaffolds: Accessing Planar and Central Chiral N,C-Palladacycles

Abstract

A selective palladation: Planar and central chiral cyclophanyl-derived mono- and binuclear N,C-palladacycles are prepared by regioselective ortho-palladation of amine- and imine-functionalized [2.2]paracyclophanes employing stepwise Pd(OAc)$_{2}$ and LiCl followed by modular treatment with PPh$_{3}$, PCy$_{3}$ and (Ph$_{2}$PCH$_{2}$)$_{2}$. The regioselective ortho-palladation mono- and bimetallic product formation was analyzed by detailed spectroscopic techniques, mass spectrometry and unambiguously confirmed by single-crystal X-ray analysis. In this report, we describe a series of cyclophanyl-derived mono- and binuclear N,C-palladacycles by regioselective ortho-palladation of amine-functionalized [2.2]paracyclophanes. Employing Pd(OAc)$_{2}$ followed by LiCl and with the subsequent modular treatment of Ph$_{3}$P, Cy$_{3}$P, and (Ph$_{2}$PCH$_{2}$)$_{2}$, this strategy allows to prepare stable cyclophanyl-derived planar and central chiral N,C-palladacycles in a highly selective manner. The regioselective ortho-palladation mono- and bimetallic product formation was analyzed by detailed spectroscopic techniques, mass spectrometry and unambiguously confirmed by single-crystal X-ray analysis