Application of Photoclick Chemistry for the Synthesis of Pyrazoles via 1,3-Dipolar Cycloaddition between Alkynes and Nitrilimines Generated In Situ
作者:Richard Remy、Christian G. Bochet
DOI:10.1002/ejoc.201701225
日期:2018.1.23
The photolysis of tetrazoles leads to the extrusion of dinitrogen and forms a reactive nitrile imine intermediate. The latter can then react in situ with alkynes in a [3+2] cycloaddition providing pyrazoles. Some reactivity trends were identified, such as a preference for electron‐poor alkynes. On the tetrazole part, there is a clear preference for either aromatic or conjugated substituents.
Palladium- and copper-catalyzed selective arylation of 5-aryltetrazoles by diaryliodonium salts
作者:Irina P. Beletskaya、Dmitri V. Davydov、Matvey S. Gorovoy
DOI:10.1016/s0040-4039(02)01325-4
日期:2002.8
Palladium(0)-catalyzed arylation of 5-aryltetrazoles in t-BuOH at 80°C with diaryliodoniumsalts proceeds in the presence of copper(II) phenylcyclopropyl carboxylate regioselectively at the N2 position.
Convenient Synthesis of Highly Functionalized Pyrazolines via Mild, Photoactivated 1,3-Dipolar Cycloaddition
作者:Yizhong Wang、Claudia I. Rivera Vera、Qing Lin
DOI:10.1021/ol7017328
日期:2007.10.1
cycloaddition procedure was successfully developed for the synthesis of polysubstituted pyrazolines. This procedure involved the in situ generation of the reactive nitrile imine dipoles using a hand-held UV lamp at 302 nm, followed by spontaneous cycloaddition with a broad range of 1,3-dipolarophiles with excellent solvent compatibility, functional group tolerance, regioselectivity, and yield.
We report the directobservation of a bent geometry for a nonstabilized nitrile imine in a metal-coordination crystal. The photoinduced tetrazole ring rupture to release N(2) appears to depend on the size of voids around the N(3)-N(4) bond in the crystal lattice. We further observed the selective formation of the 1,3-addition product when a reactive nitrile imine was photogenerated in water. Overall
Triple Orthogonal Labeling of Glycans by Applying Photoclick Chemistry
作者:Verena F. Schart、Jessica Hassenrück、Anne-Katrin Späte、Jeremias E. G. A. Dold、Raphael Fahrner、Valentin Wittmann
DOI:10.1002/cbic.201800740
日期:2019.1.18
All good things come in threes: The nitrile imine–alkene cycloaddition (photoclick reaction) was shown to be a suitable ligation reaction for metabolic glycoengineering. In combination with an inverse‐electron‐demand Diels–Alder reaction and strain‐promoted azide–alkyne cycloaddition, triplelabeling of glycans was achieved for the first time.