Nature Chemistry 9, 1256–1262 (2017); published online 12 June 2017; corrected after print 18 December 2017.

References 23–27 and 31–38 in the introductory paragraphs describe literature precedent for the activation of two E–H bonds at a transition metal centre (for E = B or C). It should be noted that experimental precedent also exists for the analogous activation of Si–H bonds and the manuscript has been modified to include additional citation of this chemistry (refs 22, 28,29,30).