[reaction: see text] A new class of triazole-based monophosphine 1 (ClickPhos) has been prepared via efficient 1,3-dipolar cycloadditions of readily available azides and acetylenes. Palladium complexes derived from these ligands provide highly active catalysts for Suzuki-Miyaura coupling and amination reactions of aryl chlorides.

The copper-catalyzed ketenimine formation reaction of 1-(o-acetamidophenyl)propargyl alcohols with various sulfonyl azides is found to undergo a concomitant intramolecular nucleophile attack to generate 1,2-dihydro-2-iminoquinolines after aromatization (via elimination of acetyl and hydroxy groups) and tautomerization. The reaction produces 4-substituted and 3,4-unsubstituted title compounds in...

Strain-promoted cycloadditions of cyclic nitrones with cyclooctynes proceed with rate constants up to 3.38 ± 0.31 M(-1) s(-1) in CD(3)CN, or 59 times faster than the analogous reaction of azides. This highly specific modular labeling strategy can be applied for direct labeling of proteins and for live cell imaging of cancer cells.

Fully deprotected alkynyl-functionalised mono- and oligosaccharides undergo CuAAC-based conjugation with water-soluble porphyrin azides in aqueous environments. The mild reaction conditions are fully compatible with the presence of labile glycosidic bonds. This approach provides an ideal strategy to conjugate tetrapyrroles to complex carbohydrates.

Conversion of carboxylic acids into acid azides using peptide coupling agents, EDC and HBTU is described. The procedure is efficient, practical and applicable to a diverse range of carboxylic acids including N-protected amino acids. Using the same reagents, one-pot synthesis of ureas, dipeptidyl urea esters and carbamates from acids has also been achieved.

Highly reactive tris-carbene Co(I) complexes [(TIMENaryl)Co]Cl react with organic azides to yield monomeric Co(III) imido complexes [(TIMENaryl)Co(NAr')](BPh4) (aryl = mes, xyl; Ar = -C6H4-CH3, -C6H4-OCH3). The cobalt-imido fragment in these complexes is electrophilic and, as a result, the imido group readily inserts into the cobalt-carbene bond, yielding bis-carbene imine cobalt complexes.

A practical and efficient amidation reaction involving aromatic aldehydes and various azides under mild conditions is described. A broad spectrum of functional groups was tolerated, and the amides were synthesized in moderate to excellent yields, presenting an attractive alternative to the currently available synthetic methods.

Tetrazolium salts are biologically active molecules that have found broad applications in biochemical assays. A regioselective synthesis of tetrazolium salts is described through a formal (3 + 2) cycloaddition. The possibility of employing simple amides and azides as starting material and the mild conditions allow a broad functional group tolerance.

We report here a new catalytic reaction in which, para-nitro azides are acylated by aldehydes to produce amides and molecular nitrogen in a single step. The transformation is believed to proceed via an electron transfer process mediated by the tert-butoxide ion, and catalysed by a thiazolium salt derived species.

Abstract The applicability of pyrones as a bioorthogonal platform was explored in inverse-electron-demand Diels–Alder (IEDDA) reactions with strained cyclooctyne. Studies showed that the are indeed suitable for IEDDA under physiological conditions. Furthermore, stable pyrone moiety could be utilized to construct easily accessible fluorogenic probes. Mutual orthogonality reaction 2-pyrones SPAAC...