Boron Perturbed Click Reactions Prompt Aromatic CH Activations

Abstract

The reaction of boron alkynes and boron azides leads to rare N 3 BC heterocycles resulting from aromatic C À H activation of benzene and toluene. While subsequent treatment with PMe 3 gave the PÀB adduct with the exocyclic boron, reaction with PtBu 3 effected deprotonation of the heterocycle to give the corresponding phosphonium salt.

Bistriazoles Connected Through a B−B Bridge, Synthesized by Highly Selective Dipolar Cycloaddition Reactions of a Diazido‐diborane(4)

“…[37] Five-membered N 3 BC heterocyclic compounds resulted from reaction between the boron azide (F 5 C 6 ) 2 BN 3 and the boron alkyne (F 5 C 6 ) 2 BC � CPh. [38] Since reactions generally require high temperature, temperaturesensitive boron azides could only be applied in exceptional cases. For example, Melen and Stephan reported several cycloadditions between dimeric dicyclohexyl boron azide, (Cy 2 BN 3 ) 2 , and electron-poor alkynes, proceeding already at room temperature to new dibora-triazole compounds.…”

“…Reactions of LiB(N 3 ) 4 and Na(N 3 ) 4 as well as several adducts of B(N 3 ) 3 with nitriles to give tetrazoles were accomplished at 80–120 °C [37] . Five‐membered N 3 BC heterocyclic compounds resulted from reaction between the boron azide (F 5 C 6 ) 2 BN 3 and the boron alkyne (F 5 C 6 ) 2 BC≡CPh [38] . Since reactions generally require high temperature, temperature‐sensitive boron azides could only be applied in exceptional cases.…”