V. Panettalemer et al., SYNTHESIS OF 24-MEMBERED, 26-MEMBERED, 32-MEMBERED AND 36-MEMBERED MACROCYCLIC POLYAMINES VIA A (2+2) CYCLIZATION PROCESS, Tetrahedron letters, 35(15), 1994, pp. 2337-2340
At high concentration, N-pertriflated polyamines and omega, omega'-dih
alogenoalkanes react to yield large polyazamacrocycles according to a
(2+2) cyclization mode.