Conformational behavior of 3-borabicyclo[3.3.1]nonanes: 1. Study of molecular dynamics in 3-methoxy-7α-phenyl-1,5-dimethyl-3-borabicyclo[3.3.1]nonane

3-Methoxy-7α-phenyl-1,5-dimethyl-3-borabicyclo[3.3.1]nonane 5 in solution at room temperature exists in the double chair conformation, as shown by NMR studies. Increasing the temperature leads to an increase in the population of the chair-boat conformation. At decreased temperature hindered rotation around the B-O bond is observed for 5. Dissolving 5 in deuteropyridine leads to the reversible formation of complex 6, which exists in the chair-boat conformation. The chair-boat conformation is also the most stable one for chelate compound 7 with a tetracoordinated boron atom.