# Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

## TL;DR

This paper introduces a new chemical method for efficiently linking molecules without metals, using specially designed compounds.

## Contribution

The novel use of electron-withdrawing substituents in octadehydrodibenzo[12]annulene derivatives to enhance strain-promoted azide–alkyne cycloaddition.

## Key findings

- Electron-withdrawing substituents increase the reaction rate of double azide addition.
- New octadehydrodibenzo[12]annulene derivatives were synthesized and applied in polymer crosslinking.
- The method is regioselective and metal-free, suitable for bioconjugation and materials research.

## Abstract

Strain-promoted azide–alkyne cycloaddition (SpAAC) is a powerful tool in the field of bioconjugation and materials research. We previously reported a regioselective double addition of organic azides to octadehydrodibenzo[12]annulene derivatives with electron-rich alkyloxy substituents. In order to increase the reaction rate, electron-withdrawing substituents were introduced into octadehydrodibenzo[12]annulene. In this report, the synthesis of new octadehydrodibenzo[12]annulene derivatives, regioselective double addition of organic azides, and an application to crosslinking polymers are described.