Synthesis and Applications of the C₂-Symmetrical Diamine 2,7-Diazabicyclo[4.4.1]undecane

Chiral diamines are particularly useful as ligands for asymmetric catalysis. In an effort to expand the library of such diamines, the synthesis and resolution of the C₂-symmetric diamine 2,7-diazabicyclo[4.4.1]undecane [(-)-1] are reported. Diamine (-)-1 has been prepared in multigram quantities from the known bicyclic diketone 7 in four steps without the need for chromatographic purification. Derivatives of (-)-1, i.e., the bis-methylated diamine (+)-5 and two diastereomeric tricyclic analogs, were evaluated as potential sparteine surrogates. The solid-state structure of the (+)-5-methyllithium complex was obtained. High levels of asymmetric induction were observed while using (+)-5 as a ligand in palladium-mediated asymmetric allylations.