Copper Catalysis with Arynes: Unlocking Site-Selective Arylation of Pyrazoles.

Arynes are among the most reactive species in organic chemistry-six-membered rings so strained that their energy rivals that of a hand grenade. Since their discovery in 1902, chemists have used arynes to achieve innovative transformations and access diverse natural products, however, their application for catalytic cross-coupling remains unrealized. A major challenge in late-stage functionalization is the selective -arylation of unsymmetric pyrazoles to create a core found in blockbuster medicines worth over nineteen billion dollars annually.

Lasso Peptides: Exploring the Folding Landscape of Nature's Smallest Interlocked Motifs.

Lasso peptides make up a class of natural products characterized by a threaded structure. Given their small size and stability, chemical synthesis would offer tremendous potential for the development of novel therapeutics. However, the accessibility of the pre-folded lasso architecture has limited this advance.

Nonthreaded Isomers of Sungsanpin and Ulleungdin Lasso Peptides Inhibit H1299 Cancer Cell Migration.

Lasso peptides are a structurally distinct class of biologically active natural products defined by their short sequences with impressively interlocked tertiary structures. Their characteristic peptide [1]rotaxane motif confers marked proteolytic and thermal resiliency, and reports on their diverse biological functions have been credited to their exceptional sequence variability. Because of these unique properties, taken together with improved technologies for their biosynthetic production, lasso peptides are emerging as a designable scaffold for peptide-based therapeutic discovery and development.

Octahedral [Pd L ] Metallosupramolecular Cages: Synthesis, Structures and Guest-Encapsulation Studies.

Four planar tripyridyl ligands (L ), 1,3,5-tris(pyridin-3-ylethynyl)benzene 1 a, 1,3,5-tris[4-(3-pyridyl)phenyl]benzene 2 a, and the hexyloxy chain functionalized derivatives 1,3,5-tris[(3-hexyloxy-5-pyridyl)ethynyl]benzene 1 b, and 1,3,5-tris[4-(3-hexyloxy-5-pyridyl)phenyl]benzene 2 b, were synthesized and used to generate a family of [Pd (L ) ](BF ) octahedral cages (L =1 a, b or 2 a, b). The ligands and cages were characterized using a combination of H, C, and DOSY nuclear magnetic resonance (NMR) spectroscopy, high resolution electrospray mass spectrometry (HR-ESI-MS), infrared (IR) spectroscopy, elemental analysis, and in three cases, X-ray crystallography. The molecular recognition properties of the cages with neutral and anionic guests were examined, in dimethyl sulfoxide (DMSO), using NMR spectroscopy, mass spectrometry and molecular modeling.