Fig. 2: Synthesis of [2]rotaxane building blocks 6·Ma and 6·Mb.
From: Masked alkynes for synthesis of threaded carbon chains
![Fig. 2: Synthesis of [2]rotaxane building blocks 6·Ma and 6·Mb.](http://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fs41557-023-01374-z/MediaObjects/41557_2023_1374_Fig2_HTML.png)
Active metal template coupling of terminal butadiyne 1 and bromoalkyne 2 in the presence of macrocycle Ma or Mb was used to synthesize rotaxanes 3·Ma and 3·Mb, which were then converted into 6·Ma and 6·Mb. Asterisk indicates yield over two steps.