Abstract
Post-assembly reaction of a dynamic covalent iminoboronate system following addition of Cp(2) Co resulted in the formation of a series of new reductively coupled dianionic dimers via C-C bond formation. The dimers formed as a mixture of BN-containing isomeric products: diastereomers rac(5) and meso(5,) with coupled five-membered rings, and enantiomeric rac(6,) with a fused six-membered ring bicyclic system from C-C bond formation and rearrangement of the B-N bonds. Each isomer was identified using (1) H NMR spectroscopy in combination with single crystal X-ray structure determination. Interestingly, interconversion between the coupled five-membered rings (rac(5) ) and fused bicyclic systems (rac(6) ) was found to occur through an unprecedented breaking and reforming of the B-N covalent bond. Further, the coupled products could be converted quantitatively back to their iminoboronate precursors with addition of the electron abstractor Ph(3) C(+) .