Novel tricyclic diamines 1. Synthesis of 1,4-diazaisotwistane and 1,4-diazahomoisotwistane as constrained 3-aminoquinuclidine isosteres

•Novel 1,4-diazaisotwistane and 1,4-diazahomoisotwistane tricylic diamines prepared as aminoquinuclidine isosteres.•Synthesis relies on saturation of aromatic heterocycle followed by intramolecular cyclization.•Structures of novel tricycles confirmed by X-ray crystallography.