Huge molecular fragment quantum tunnels in everyday lab reaction

The Curtius rearrangement – a reaction discovered over 130 years ago – has given up a long guarded secret: it can proceed through an extremely rare case of heavy atom quantum tunnelling. Now, a team around Manabu Abe from Hiroshima University, Japan, and Xiaoqing Zeng from Soochow University, China, has discovered that a whole trifluoromethyl group tunnels in the Curtius rearrangement of trifluoroacetyl azide into trifluoroacetyl isocyanate.