Reactions of tetrafluoroethene oligomers. Part 9. Some reactions of perfluoro(1-ethyl-1-methylpropyl)(s-butyl)ethanolide (an α-lactone)

Abstract

The ethanolide (1), prepared by hypochlorite-mediated epoxidation of the ketene CF₃(C₂F₅)₂ C[C₂F₅(CF₃)CF]CCO (2), decomposed when warmed at 90 °C for 30 min to give the ketone CF₃(C₂F₅)₂CCOCF(CF₃)C₂F₅(3). Reaction of compound (1) with either triethylamine or trimethylamine afforded the olefin (E/Z)-CF₃(C₂F₅)₂CCHC(CF₃)C₂F₅(4). Treatment of compound (1) with secondary amines R₂NH (R = Et, R₂[CH₂]₅) or primary amines RNH₂(R = c-C₆H₁₁ or Bu^t) afforded oxo amides of the type CF₃(C₂F₅)CFCOCONR₂(5) and (6) and CF₃(C₂F₅)CFCOCONHR (7) and (8). With ethylamine and isopropylamine the isolated products were the corresponding oxamides and the olefin (4). With sodium methoxide three products were formed, a trace of olefin (4), 2,4-dimethoxyperfluoro-3-methylpent-2-ene (10), and the oxo ester CF₃(C₂F₅)CFCOCO₂Me (11). Sodium ethoxide yielded the olefin (4), the oxo ester CF₃(C₂F₅)CFCOCO₂Et (12), and the olefin CF3CFC(CF₃)CF(CF₃)OEt (13). Reaction of compound (1) with methylmagnesium iodide and ethylmagnesium iodide afforded the esters C₂F₅(CF₃)CC(CO₂Me)C(Me)(CF₃)C₂F₅(14) and C₂F₅(CF₃)CC(CO₂Et)C(Et)(CF₃)C₂F₅(15) respectively. Treatment of compound (1) with methyl-lithium gave a mixture of two products, the esters (14) and C₂F₅(CF₃)(Me)CC(CO₂Me)C(Me)CF₃(16), by what appears to be an unusual attack on the ring oxygen. Reaction of compound (1) with ethanethiol gave the ester C₂F₅(CF₃)CFCOCOSEt (17) and the olefin C₂F₅(CF₃)CC(CF₃)SEt (18). Compound (1) on reaction with ammonia gave oxamide and the unusual cyanodi-imine CF₃C(NH)CH(CN)C(NH)CF₃(9). Reaction of compound (1) with tributyl- or triphenyl-phosphine gave olefin (4) again by reaction on the ring oxygen.