Steric shield leads boron to aromatic rings’ most remote region

A steric shield – a simple bulky cation – makes it possible to attach boron to aromatic rings’ rarely accessed, remote para position. Unlike other para C–H borylation reactions, the method requires neither an elaborate catalyst nor bespoke ligands. ‘I think others will turn to this method because of its ease,’ says Michigan State University’s Robert Maleczka who, together with Milton Smith, led one of the two teams that independently developed the reaction.