Cu-Catalyzed Three-Component Alkene Carboamination: Mechanistic Insights and Rational Design to Overcome Limitations.

Herein, we report mechanistic investigations into the Cu-catalyzed three-component carboamination of alkenes with α-halo carbonyls and aryl amines via an oxocarbenium intermediate. Monitoring the reaction reveals the formation of transient atom transfer radical addition (ATRA) intermediates with both electron-neutral and deficient vinyl arenes as well as unactivated alkenes. Based on our experimental studies and density functional theory calculations, the oxocarbenium is generated through atom transfer and subsequent intramolecular substitution.

Structural Insight on Supramolecular Polyion Salts: Inositol Hexaphosphate Enclosed in Cationic Macrocyclic Clusters.

Supramolecular macrocyclic forces have been used to trap phytate, myo-inositol-1,2,3,4,5,6-hexakisphosphate, a key bioanion with multiple roles in metabolic processes. Due to the complex chemistry of six multivalent phosphates surrounding the small, cyclic inositol framework, crystallographic information of simple phytate salts has been elusive. This report represents a combined crystallographic, theoretical, and solution binding investigation of a supramolecular macrocyclic complex of phytate.

Newly identified C-H⋯O hydrogen bond in histidine.

New Cδ-H⋯O histidine hydrogen bonding interactions in various proteins are identified by neutron diffraction and computationally characterized. Neutron diffraction data shows several H-bond motifs with the Cδ-H moiety in histidine side chains, including interactions in β-sheets and with coordinated waters, mostly with histidinium and τ-tautomers. In yellow protein, an active site histidine H-bonds Cδ-H to a main chain carbonyl while the Cε-H bond coordinates a water molecule.