Treatment of cyclopropylmethanols with pyridinium poly(hydrogen fluoride) in chlorobenzene-diisopropylamine in the presence of KHF2 gave selectively homoallylic fluorides.
Insecticidal, acaricidal, nematicidal or molluscicidal compounds of formula (I)
wherein Y is a single bond, C=O, C=S or S(O)q where q is 0, 1 or 2; and R1, R2, R3, R4, R8, R9 are R10 are as defined in the claims or salts or N-oxides thereof, processes for preparing them and compositions containing them.