Nature Communications 7: Article number: 13672 (2016); Published 30 November 2016; Updated 23 December 2016

Figures 1 and 6 of this Article contain errors that were introduced during the production process. In Fig. 1, the reaction conditions required to convert 1 to 7d, 2e to 9c and 1d to 10d should be described by (i) and not (iv). In Fig. 6, the arrow representing the monomer fragment of 448 Da is pointing to the wrong dashed spectral line. The corrected versions of Figs 1 and 6 are shown below as Figs 1 and 2, respectively.

figure 1

Figure 1

figure 2

Figure 2