Highly selective synthesis of [(perfluoroalkyl)methyl]oxiranes (by the addition of iodoperfluoroalkanes to allyl acetate)

Mixtures of regioisomeric adducts of monoiodoperfluoroalkanes R-F-I (R-F = C4F9, C6F13 C8F17) with allyl acetate, RFCH2CHICH2OAc (1a-1c) and rearranged adducts RFCH2CH(OAc)-CH2I (2a-2c), were converted chemoselectively to the corresponding oxiranes RFCH2CH(-O-)CH2 (3a-3c) in yields of 94-96% (total yields of the two-step synthesis starting from R-F-I were 85-87%). The chemoselectivity of the oxirane formation appeared to be very dependent on the solvent used. Dependence on the reaction conditions on formation of byproducts RFCH=CHCH2OAc (4a-4c) and RFCH=CHCH2OH (5a-5c) in the epoxidation reaction was studied. (C) 1997 Elsevier Science S.A.