Skeletal Editing—Nitrogen Deletion of Secondary Amines by Anomeric Amide Reagents

Late-stage modification is highly desirable for the diversification and modification of biologically active compounds. Peripheral editing (e.g., C−H activation) has been the predominant methodology, whereas skeletal editing is in its infancy. The single-atom N-deletion using anomeric amide reagents constitutes a powerful tool to modify the underlying molecular skeletons of secondary amines. N-pivaloyloxy-N-alkoxyamide is easily prepared on a large scale and promotes C−C bond formation in good yields under the extrusion of N2 for a variety of (cyclic) aliphatic amines. The exploitation of widely available amines allows the use of existing amine synthesis protocols to translate into the construction of new C−C bonds, enabling ring contraction and the potential for structure optimization of biologically active compounds

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

Design and Synthesis of a [2.2]Paracyclophane-based Planar Chiral Dirhodium Catalyst and its Applications in Cyclopropanation Reaction of Vinylarenes with alpha-Methyl-alpha-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 withtert-butyl alpha-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 beta-hydride migration at room temperature with high diastereoselectivity.Peer reviewe

C-P bond formation of cyclophanyl-, and aryl halides via a UV-induced photo Arbuzov reaction : a versatile portal to phosphonate-grafted scaffolds

A new versatile method for the C-P bond formation of (hetero)aryl halides with trimethyl phosphite via a UV-induced photo-Arbuzov reaction, accessing diverse phosphonate-grafted arenes, heteroarenes and co-facially stacked cyclophanes under mild reaction conditions without the need for catalyst, additives, or base is developed. The UV-induced photo-Arbuzov protocol has a wide synthetic scope with large functional group compatibility exemplified by over 30 derivatives. Besides mono-phosphonates, di- and tri-phosphonates are accessible in good to excellent yields. Mild and transition metal-free reaction conditions consolidate this method's potential for synthesizing pharmaceutically relevant compounds and precursors of supramolecular nanostructured materials.Peer reviewe

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

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

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

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 Ph3P, Cy3P, and (Ph2PCH2)(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.Peer reviewe

Design Strategies for Structurally Controlled Polymer Surfaces via Cyclophane‐Based CVD Polymerization and Post‐CVD Fabrication

Molecular structuring of soft matter with precise arrangements over multiple hierarchical levels, especially on polymer surfaces, and enabling their post-synthetic modulation has tremendous potential for application in molecular engineering and interfacial science. Here, recent research and developments in design strategies for structurally controlled polymer surfaces via cyclophane-based chemical vapor deposition (CVD) polymerization with precise control over chemical functionalities and post-CVD fabrication via orthogonal surface functionalization that facilitates the formation of designable biointerfaces are summarized. Particular discussion about innovative approaches for the templated synthesis of shape-controlled CVD polymers, ranging from 1D to 3D architecture, including inside confined nanochannels, nanofibers/nanowires synthesis into an anisotropic media such as liquid crystals, and CVD polymer nanohelices via hierarchical chirality transfer across multiple length scales is provided. Aiming at multifunctional polymer surfaces via CVD copolymerization of multiple precursors, the structural and functional design of the fundamental [2.2]paracyclophane (PCP) precursor molecules, that is, functional CVD monomer chemistry is also described. Technologically advanced and innovative surface deposition techniques toward topological micro- and nanostructuring, including microcontact printing, photopatterning, photomask, and lithographic techniques such as dip-pen nanolithography, showcasing research from the authors’ laboratories as well as other\u27s relevant important findings in this evolving field are highlighted that have introduced new programmable CVD polymerization capabilities. Perspectives, current limitations, and future considerations are provided