CO/CO and NO/NO coupling at a hidden frustrated Lewis pair template.

-Allyltetramethylpiperidine is readily isomerized to the corresponding enamine by treatment with catalytic amounts of B(CF). It adds HB(CF) 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 COB heterocycle. In contrast the enamine/HB(CF) Lewis pair reacts with two molar equiv. of nitric oxide by head to head coupling. This reaction probably proceeds equilibrium with the corresponding vicinal N/B Lewis pair. Most products were characterized by X-ray diffraction.