Synthesis of 2,6,10,14,18,22-hexaazaspiro[11.11]tricosane, the first example of a spiro aza crown derived from 2,2-bis(aminomethyl)propane-1,3-diamine

2,6,10,14,18,22-Hexaazaspiro[11.11]tricosane 1 has been prepared in seven steps from pentaerythritol. The key steps include two successive cyclizations by displacement of two tosyloxy groups from the appropriate pentaerythritol derivatives (4; 6) with 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), each reaction being followed by sodium borohydride reduction. Hydrolysis of the spiro bis(hexahydro-1H,4H,7H-3a,6a,9a-triazaphenalene) formed 1.