CO/CO and NO/NO coupling at a hidden frustrated Lewis pair template† †Electronic supplementary information (ESI) available: Experimental and analytical details, spectral data and crystallographic data. CCDC 1506872–1506879. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc04459j Click here for additional data file. Click here for additional data file.

N-Allyltetramethylpiperidine is readily isomerized to the corresponding enamine by treatment with catalytic amounts of B(C6F5)3. It adds HB(C6F5)2 at the nucleophilic enamine carbon atom to form a C/B Lewis adduct. This reacts with two molar equivalents of carbon monoxide by selective head to tail coupling to give a five-membered C2O2B heterocycle. In contrast the enamine/HB(C6F5)2 Lewis pair reacts with two molar equiv. of nitric oxide by head to head coupling. This reaction probably proceeds via equilibrium with the corresponding vicinal N/B Lewis pair. Most products were characterized by X-ray diffraction.