Unlocking the N² Selectivity of Benzotriazoles: Regiodivergent and Highly Selective Coupling of Benzotriazoles with Allenes

Abstract

The rhodium-catalyzed, highly N 2 -and N 1 -selective coupling of benzotriazoles with allenes is reported. The exceptionally high N 2 and N 1 selectivities were achieved by using a rhodium(I)/DPEphos and rhodium(I)/JoSPOphos catalyst, respectively. This method permits the atom-economic synthesis of valuable branched N 2 -and N 1 -allylated benzotriazole derivatives and allows for preliminary studies of their reactivity.

Zinc‐Catalysed N‐Iodosuccinimide‐Enabled Selective N2‐Olefination of Benzotriazoles with Alkenes

“…In 2014, Breit et al. reported a highly N 2 ‐ and N 1 ‐selective allylation of benzotriazoles with allenes using Rh(I)/DPEphos or Rh(I)/JoSPOphos catalysts (equation 1, Scheme a). Very recently, Zhang and Sun found a novel Rh‐catalysed highly selective N 2 ‐alkylation of benzotriazoles that uses diazo compounds or enynones, affording N 2 ‐alkylated benzotriazoles in good to excellent yields (equation 2, Scheme a) …”

Copper(II)-Catalyzed C–H Nitrogenation/Annulation Cascade of Ketene N,S-Acetals with Aryldiazonium Salts: A Direct Access to N2-Substituted Triazole and Triazine Derivatives

“…However, N 2 -substituted 1,2,3-triazoles can not be readily accessed, and their direct synthesis has remained a great challenge due to the uncontrollable regioselectivity of the conventional synthetic reactions. Thus, N−H functionalization of NH-1,2,3-triazoles has usually been used to make N 2substituted 1,2,3-triazole derivatives, including N 2 -arylation, 7 alkylation, 8 allylation, 9 and vinylation 10 (Scheme 2a). Oxidative cyclization of arylhydrazones 11 and azobenzenes, 12 copper(I)-catalyzed carboamination cascade between vinyl azides and aryldiazonium salts, 13 and coupling of oxime acetates with diazonium tetrafluoroborates 14 have also been applied for the same purpose.…”

Chemo-, Regio-, and Enantioselective Rhodium-Catalyzed Allylation of Triazoles with Internal Alkynes and Terminal Allenes

“…Among these, we described N 1 -and N 2 -selective rhodium-catalyzed additions of benzotriazoles to aliphatic terminal allenes (Scheme 1) depending on the rhodium catalyst employed. 7,8 Given the pharmacological importance of chiral N 1 -alkylated triazoles, we decided to develop a related asymmetric catalytic variant. We anticipated that by the choice of an appropriate JosPOphos ligand there might be an opportunity to control enantioselectivity upon N 1 -selective addition of triazoles to internal alkynes and terminal allenes.…”