Recently, the lead of Biobased Polymer Group, Professor WAN Xiaobo from Qingdao Institute of Bioenergy and Bioprocess Technology made considerable progress in the synthesis of diazocines---a potential building block for artificial muscles.

Diazocine is anti-aromatic and adopts boat conformation in its neutral state. It becomes aromatic and switches to planar conformation when it is reduced and this process is reversible (Figure 1). The boat-to-planar conformation change lead to the change of the distance between the two terminals of the molecule and could be considered as the a new type of building blocks for artificial muscles.

Figure 1. The reversible conformation change of diazocines.

The traditional synthetic strategy towards diazocines involves the condensation reaction of 2-aminobenzophenone, which is time-consuming and atom inefficient. Professor Wan’s group found a new method for the synthesis of diazocines, which involves an unprecedented [2+2] cyclization between two 2-Benzoylbenzoyl azides (Scheme 1). This strategy is atom efficient and requires much less time.

Scheme 1. The new synthetic strategy towards diazocines.

This work was published in the most recent Organic Letters: http://pubs.acs.org/doi/pdf/10.1021/ol102957c