Oxolane was fluoroalkylated by its photoadditions under atmospheric pressure. Monofluoro-alkylations were carried out with hexafluoropropene (1) and perfluorovinyl ethers C3F7O-[CF(CF3)CF2O](n)-CF=CF2 (2-4, n = 0-2) by direct photoexcitation of the olefins to give high yields of addition products 9-12 (81-94%). The reactions were completely regioselective at the oxolane molecule and almost completely regioselective (93-99%) at the double bond of fluoro-olefins; no bis-fluoroalkylated oxolanes were detected. The completely selective introduction of a second fluoroalkyl into position 5 of the oxolane molecule was accomplished by acetone-sensitised photoaddition of 2-fluoroalkylated oxolanes 9, 10 to fluoro-olefins 1 and 2. By products from reactions of the dimethylketyl radical which is formed in the initiation step were isolated and have given some evidence about the reaction mechanism that is discussed.
New fluorination of organic compounds using thermodynamically unstable nickel fluorides
作者:Neil Bartlett、Richard D. Chambers、Alex J. Roche、Robert C. H. Spink、Lisa Chacón、J. Marc Whalen
DOI:10.1039/cc9960001049
日期:——
Replacement of hydrogen by fluorine in a variety of organic compounds is accomplished with high efficiency in liquid hydrogen fluoride (aHF), at or below 20 degrees C, using the thermodynamically unstable fluorides RNiF(3) and NiF4, the latter prepared in situ from K2NiF6 with BF3.