Long-range proton-fluorine spin-spin coupling. Further evidence for a 'direct' mechanism

Abstract

A variable temperature p.m.r. study of outho- and peri-acetyl substituted fluoro-naphthalenes (including o-fluoroacetophenone) has been carried out. Further, 1-fluoro- 8-methylnaphthalene (previously unknown) has been synthesized and its p.m.r. spectra has been measured at various temperatures. The data, together with ¹⁹F substituent chemical shifts (SCS) for ortho-substituted cyanofluoronaphthalenes, provide further strong support for a through-space coupling mechanism (J_Me,F).