Reinvestigation of the substituent effects of fluorine on the H-1 NMR chemical shifts of the adjacent methylene group in fluorinated [2.2]paracyclophanes

Introduction of a fluorine substituent into an aromatic ring of [2.2]paracy clophane causes distinct shielding and deshielding effects at the anti- and syn-protons, respectively, of the adjacent bridge methylene group. A recen t contradictory claim in the literature was disproved by 2D H,H-NOESY, long -range H,H-COSY and H,C-HMBC experiments. Copyright (C) 1999 John Wiley & S ons, Ltd.