Acid-mediated synthesis of fully substituted 1,2,3-triazoles: multicomponent coupling reactions, mechanistic study, synthesis of serine hydrolase inhibitor and its derivatives

Neighboring Nitrogen Atom-Induced Reactions of Azidoacetyl Hydrazides, including Unexpected Nitrogen-Nitrogen Bond Cleavage of the Hydrazide

We studied the hydrazide compounds of the α-azidoacetyl group, which showed specific click reactivity by the intramolecular hydrogen bonding between the azido group and the N-H of the hydrazide moiety. In the competitive click reactions with a general alkyl azide, both traceless and non-traceless Staudinger-Bertozzi ligation occurred azide-site-selectively by the acceleration effect of the hydrogen bonding. However, the product obtained from the traceless reaction was further transformed into heterocyclic compounds. In addition, in an attempt at a synthesis of naphthalimide-possessing azidoacetyl hydrazide, nitrogen-nitrogen bond cleavage of the azidoacetyl hydrazides occurred to give the reduced amine product. These unexpected results could help design molecules for the successful Staudinger-Bertozzi ligation of the hydrazide compounds and develop a new nitrogen-nitrogen bond cleavage method.

Taming the reactivity of alkyl azides by intramolecular hydrogen bonding: site-selective conjugation of unhindered diazides

The intramolecular hydrogen bonding in the α-azido secondary acetamides (α-AzSAs) enabled site-selective integration onto the diazide modular hubs even without steric hindrance.

Sequential conjugation methods based on triazole formation and related reactions using azides

The recent remarkable progress in azide chemistry has realized sequential conjugation methods with selective 1,2,3-triazole formation. On the basis of the diverse reactivities of azides and azidophiles, including terminal alkynes and cyclooctynes, various selective reactions to furnish triazoles and a wide range of platform molecules, such as diynes, diazides, triynes, and triazides, have been developed so far for bis- and tris(triazole) syntheses. This review highlights recent transformations involving selective triazole formation, allowing the efficient preparation of unsymmetric bis- and tris(triazole)s using diverse platform molecules.

An Efficient Approach to Phosphorylated Isoindoline Fused with Triazoles via Zn-Catalyzed Cascade Cyclization of 2-Propynol Benzyl Azides and Diarylphosphine Oxides

An efficient approach for the synthesis of phosphorylated isoindoline fused with triazoles via Zn(OTf)₂-catalyzed cascade cyclization of easily prepared ortho-propynol benzyl azides and diarylphosphine oxides is developed. The transformation occurred smoothly in moderate to excellent yields and tolerated various propargylic alcohol substrates.

Theoretical investigation of Banert cascade reaction

Computational inside of Banert cascade reaction for triazole formation is studied with B3LYP/6-31G(d,p) level of theory. The reaction proceeds mainly by SN2 initial chloride displacement rather than SN2'-type attack. Furthermore, according to the rate of reaction calculation, SN2 displacement is much faster than SN2' displacement in the order of 8. The [3,3]-sigmatropic rearrangement for the conversion of propargyl azide into triazafulvene has been proved as the rate-determining step having highest activation energy parameter. Solvent effect on total course of reaction has been found negligible. Furthermore, effects of different density functional theory functionals and functional groups on activation energies of [3,3]-sigmatropic rearrangement of propargyl azide were also studied. BHHLYP, ωB97XD, M062X and BMK calculated ΔG^‡ are consistent with B3LYP.

Recent advances in the tandem reaction of azides with alkynes or alkynols

Over the past few decades, the development of versatile methodologies to employ azides as aminating agents for the formation of nitrogen-containing compounds has attracted significant attention in synthetic chemistry.