The ring-opening Si-fluorination of a variety of azasilole derivatives cyclo-1-(iPr2Si)-4-X-C6H3-2-CH2NR (4: R = 2,6-iPr2C6H3, X = H; 4a: R = 2,4,6-Me3C6H2, X = H; 9: R = 2,6-iPr2C6H3, X = tBuMe2SiO; 10: R = 2,6-iPr2C6H3, X = OH; 13: R = 2,6-iPr2C6H3, X = HCCCH2O; 22: R = 2,6-iPr2C6H3, X = tBuMe2SiCH2O) with different 19F-fluoride sources was studied, optimized and the experience gained was used in a translational approach to create a straightforward 18F-labelling protocol for the …