REACTION OF PERFLUOROALKYL IODIDES WITH ELECTRON-DEFICIENT OLEFINS UNDER UV IRRADIATION

The reaction of perfluoroalkyl iodides 1 with acrylates, acrylic acid, acrylamide, and acrylonitrile has been investigated. In the presence of a catalytic amount of palladium(0), the reaction of R(f)I with ethyl acrylate produces: mostly polymer. Under irradiation with 254 nm UV light, perfluoroalkyl iodides react with. ethyl acrylate to give high yields of the 1:1 addition products (74-88% isolated yield, CnF(2n+1)CH(2)CHICO(2)Et) and small amounts of 1:2 adducts (<10% NMR yield) at ambient temperature. The functionalized iodide 5-iodo-3-oxaoctafluoropentanesulfonyl fluoride also reacts with ethyl acrylate to give the 1:1 adduct in 88% yield. However, it has been found that the reaction selectivity is related to the length of the perfluoroalkyl group in 1 when methyl acrylate is employed in the reaction under similar conditions. Both 1:1 (56-76%) and 1:2 adducts [CnF(2n+1)- CH2CH(CO(2)Me)CH(2)CHICO(2)Me, 24-34%] are formed when methyl acrylate reacts with short-chain perfluoroalkyl iodides [CnF(2n+1)I, n less than or equal to 4], whereas the reaction of perfluorohexyl or longer chain perfluoroalkyl iodides [CnF(2n+1)I, n greater than or equal to 6] gives predominantly the 1:1 addition products (>85%). The formation of the 1:2 adduct can be efficiently suppressed by using excess R(f)I in the reaction. The reaction of N,N-dimethylacrylamide with perfluoropropyl iodide (1a) produces exclusively the 1:1 adduct. Products from the further elimination, reduction, and decarboxylation of the 1:1 and 1:2 adducts are observed when 1a reacts with methyl methacrylate under similar conditions. The reaction of 1a with acrylonitrile produces the 1:1 and 1:2 adducts in 53% and 47% yields, respectively. An addition-reduction product, n-C3F7CH2CH2CO2H (68%), is obtained in the reaction of acrylic acid with 1a.