Comparison of the reactivity of CF3OX (X = Cl, F) with some simple alkenes

Abstract

5H))-furanone (7b) in 78% and 15% yields, respectively. 6b: colorless oil; MS m / e 218; IR (neat) 1765 cm-' (C=O). Anal. Calcd for C13H1403: C, 71.54; H, 6.47. Found: C, 71.50; H, 6.44. Hydrogenation of 6a. Into a solution of 6a (408 mg, 2.0 "01) in methanol (20 mL) was added Pd/C (5%, 100 mg), and the mixture was stirred for 18 h at room temperature under a hydrogen atmosphere. The catalyst was removed by filtration, and the filtrate was evaporated to give a mixture of diastereomers of 3,4-dihydro-5-methoxy-4-methyl-3-phenyl-2(5~-furanone @a): 406 mg; a colorless oil; IR (neat) 1775 cm-' (C==O). The 40()-MHz 'H NMR spectrum showed four sets of signals: b 0.69,0.72, 1.05, and 1.15 for methyl protons and 6 3.52, 3.49, 3.48, and 3.56 for methoxy protons. The isomer ratio (82:l:l) was determined from the peak areas of the methoxy protons. The resonances for major component are as follows: 6 0.69 (d, 3 H, Me, J = 7.3 Hz), 2.85 (dqd, 1 H, CHMe,J = 9.8, 7.3,and 5.4 Hz), 3.52 (s, 3 H, OMe), 3.87 (d, 1 H, CHPh,J = 9.8 Hz), 5.37 (d, 1 H, OCHO, J = 5.4 Hz), 7.18-7.33 (m, 5 H, Ph). Carbonylation of la in Ethanol in the Presence of Rh4-(CO),, and Various Bases (Table I). Into a 30-mL glass tube containing a Teflon-coated magnetic stirring bar were added l a (0.18 g, 1.0 mmol), Rh,(C0)12 (19 mg, 0.025 mmol), a base (1.0 mmol), and ethanol (15 mL), and the tube was placed into a 50-mL stainless-steel autoclave. The autoclave was sealed, flushed twice with carbon monoxide, pressurized to 40 kg/cm2, and heated with stirring at 125 OC for 6 h. The reaction mixture was analyzed by GC. The results are shown in Table I.Alcoholysis of 3b. A mixture of compound 3b (100 mg, 0.36 mmol) and Na2C03 (106 mg, 1.0 mmol) in ethanol (15 mL) was stirred at 150 "C for 6 h under 50 kg/cm2 of carbon monoxide in the same way described above. GC analysis of the reaction mixture indicated the presence of 5 (81 mg) and 3b (14 mg). Registry No. la,Reactions of CF30X (X = C1, F) with a variety of simple alkenes were carried out to compare the regio-and stereoselectivity of the additions to carbon-carbon double bonds. The observed addition products with CF30Cl are consistent with an electrophilic syn addition. With CF30F the observed products indicate a different regioselectivity and low stereoselectivity, consistent with a free-radical addition.

Kinetics and mechanism of the thermal gas‐phase oxidation of perfluorobutene‐2 in presence of trifluoromethyl hypofluorite

“…The synthetic aspects of the thermal addition of CF 3 OF to several haloalkenes have been reported by Johri and DesMarteau 25 and Sekiya and Ueda 26. In their works the trifluoromethylhaloalkyl ethers were the main products.…”

“…The high pressure limit values of 1.5 × 10 9 and 1.26 × 10 9 dm 3 mol −1 s −1 were reported for the rate constants for the O 2 addition to CF 3 • 43 and CF 3 CFHO • 44, respectively. The rate constants for the reactions of haloalkyl radicals with O 2 exceed those of fluorine atom abstraction from CF 3 OF by several orders of magnitude 23, 24, 25, 46. Then the contribution of reaction (25) to the disappearance of CF 3 OF and to the generation of CF 3 O • radicals must be very small, notwithstanding these few radicals contributing to initiate new chains.…”

New perfluorovinylethers through the bis(fluoroxy)difluoromethane (BDM) chemistry

“…This procedure is exactly the opposite of the methodology suggested in the literature in order to obtain high yield of hypofluorite addition products, where the addition order is reversed [11,12]. Hypofluorites are indeed susceptible to thermo or chemical self-decomposition that can cause very low addition yield or, in some cases, extended decomposition.…”

“…Due to the unique properties of the O-F bond in the organic hypofluorite, this can act as a source of electrophilic fluorine [9], electrophilic alkoxylium species [10] as well as alkoxy radicals [11].…”

The use of perfluoroalkyl hypofluorites for an efficient synthesis of perfluorinated ethers characterized by low Ostwald coefficient

“…In order to remove the majority of the overloaded hypofluorite from the bulk, the liquid phase has been stripped with an stream of 4 nL/h of helium for abut 30 min at the temperature between À80 and À90 8C, after that maintaining the temperature in the range À80 to À90 8C about 2 ml of CFCl CFCl have been added in the reactor to eliminate the reaming traces of hypofluorite. The traces of CF3OF react completely with CFCl CFCl producing CF 3 O-CFCl-CF 2 Cl [22].…”