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The syntheses of racemic and homochiral [4.4]-spirolactams, starting from L-proline, in good yields are described. Reduction of the lactam carbonyl group of spirolactams, containing chiral substituents on the lactam nitrogen, with lithium aluminium hydride, gives a series of homochiral [4.4]-spirodiamines. The crystal structure of one of these spirodiamines on complexation with zinc chloride was obtained. Interestingly it showed a hydrogen-bonded dimeric structure, where the monomers are diastereoisomeric diamines.
Kelleher, F., Kelly, S,. McKee, V., : Spirobicyclic Diamines. Part 3: Synthesis and Metal Complexation of Proline-Derived [4,4]-Spirodiamines. Tetrahedron, Vol. 63 (37) 10th Septemner, 2007, pp. 9235-9242, DOI : 10.1016/j.tet. 2007.06.050