A FACILE 2-STEP SYNTHESIS OF (OMEGA-1)-FLUOROALKAN-OMEGA-OLIDES - INFLUENCE OF A VICINAL FLUORINE SUBSTITUENT IN NUCLEOPHILIC SUBSTITUTIONS

(omega-1)-Fluoralkan-omega-olides 3 of medium to large ring size can e asily be synthesised in a facile two-step procedure by bromofluorinati on of terminally unsaturated fatty acids I with NBS/Et(3)N . 3HF and s ubsequent cyclisation with K2CO3 in dimethyl sulfoxide. Electronic and conformational changes induced by the vicinal fluorine substituent in the transition state of S(N)2-cyclisation step (calculated by the AM1 -method) were found to be responsible for a certainly hindered cyclisa tion of the monofluorinated compounds 2 in comparison with their non-f luorinated analogues. Copyright (C) 1996 Elsevier Science Ltd