Most reported reactions with electrophilic fluorinating reagents involve transformation of carbon-hydrogen bonds to carbon-fluorine bonds where the hydrogen atom is attached to either a carbon atom that is sp2 hybridised (alkenes, aromatics, carbonyl derivatives, etc) or to a carbon atom that bears a negative charge (carbanions, etc) or which must form, for example, an enol before fluorination can occur as with B-dicarbonyl compounds.

Selective transformation of carbon-hydrogen bonds to carbon-fluorine bonds, in which the <BR> <BR> <BR> hydrogen atom is attached to a fully saturated unactivated sp hybridised carbon atom, in a simple, one-step process would be particularly advantageous but fluorination of saturated systems is very difficult. Conversion of carbon-hydrogen bonds to carbon-fluorine bonds at low temperature in saturated systems such as decalin and various steroid derivatives using elemental fluorine has been reported in Tetrahedron Lett., 1984,25,1947. However, fluorine is a corrosive, toxic gas and requires the use of specialist equipment.

According to the present invention there is provided a method of selectively fluorinating an <BR> <BR> <BR> organic compound at an unactivated saturated sp3 hybridised carbon atom, the method comprising reacting the compound with a fluorinating agent containing an N-F bond.

The present invention enables direct fluorination of a saturated sp3 hybridised carbon atom to be accomplished efficiently without the disadvantages associated with using fluorine gas described above. <BR> <BR> <BR> <BR> <BR> <BR> <P>The method typically comprises substituting a hydrogen atom on the saturated sp3 hybridised carbon atom by a fluorine atom. <BR> <BR> <BR> <BR> <BR> <BR> <P>The saturated sp3 hybridised carbon atom may be bonded to three other carbon atoms and a hydrogen atom, i. e. a tertiary carbon atom.

The saturated sp hybridised carbon atom may be bonded to two other carbon atoms and two hydrogen atoms, i. e. a secondary carbon atom.

The saturated carbon atom may form part of a cyclic structure.

Where the saturated carbon atom is a tertiary carbon atom it may form part of a cyclic structure such as decalin or adamantane. Where the saturated carbon atom is a secondary carbon atom it may form part of a cyclic structure.

Advantageously the saturated carbon atom does not need to be bonded to groups such as carbonyl groups as in the fluorination of e. g. B-dicarbonyl compounds. <BR> <BR> <BR> <BR> <BR> <BR> <P>The term unactivated saturated sp carbon atom used herein means a saturated sp3 hybridised carbon atom not directly bonded to any functional group. That is to say, any carbon atom which is part of a functional group (e. g. carbonyl C=O) or is bearing a functional group (e. g.

C-OH) must be at least two atoms distant from the carbon which is bonded to the hydrogen atom that is replaced by fluorine. In the prior art, functional groups such as for example carbonyl were directly bonded, i. e. less than two carbons distant, to the carbon atom which is bonded to the hydrogen atom that is replaced by fluorine. Thus, in the prior art, the functional group would activate the carbon-hydrogen bond on the saturated carbon atom.

The fluorinating agent may be any electrophilic fluorinating agent containing an N-F bond.

The fluorinating agent may, in particular, comprise one of the following: an N- fluoropiperidine, an N-fluoro pyridone, an N-fluorosulphonamide, an N-fluoropyridinium salt, an N-fluoroimide or an N-fluorodiazabicycloalkane or similar reagents.

Preferably, the fluorinating agent is an N-fluorinated diazoniabicycloalkane, i. e. one of the class of reagents known commercially as Selectfluor (Trade mark) reagents. A Selectfluor (Trade mark) reagent is shown schematically in Figure 1.

More preferably the fluorinating agent is an N-fluorinated 1,4-diazoniabicyclo- [2.2.2] octane derivative.

Most preferably the fluorinating agent is a 1-alkyl-4-fluoro-1,4-diazoniabicyclo [2.2.2] octane salt, particularly a 1-chloromethyl-4-fluoro-1,4-diazabicyclo [2.2.2] octane salt. Preferably the salt is a bis (tetrafluoroborate) salt.

Selectfluor (Trade mark) reagent have been described previously in detail, for example, in US patent no. 5,442,084. Known preferred substituents, counter ions and other features of Selectfluor (Trade mark) reagents are incorporated herein by reference. In particular, there is incorporated herein by reference those features described in US patent no. 5,442,084 at column 3 lines 11 to 25 and at column 5 line 36 to column 7 line 10.

The present invention may be used to convert a wide range of organic substrates such as 2,10,11,12,13,14 and 15 shown in Figure 2 to the corresponding fluorinated analogues 3,4,5,6,7,8 and 9 shown in Figure 3.

In structures 2,10,11,12,13,14,15 and 8,9, the groups Ri, R2, R3, R4, R5, R6 and R7 may be selected from hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl, substituted aryl, etc. Where any of the groups Ri, R2, R3, R4, R5, R6 and R7 is an alkyl, cycloalkyl or aryl substituent, the said group may include one or more optional substituents or hetero-atoms.

The structures represented by formulae 4,5,6,8,9,10,11,12,14 and 15 are cyclic and n may be an integer in the inclusive range from 1 to 8.

Preferably, the fluorination is conducted in a solvent. Preferably the solvent comprises a largely inert substance such as acetonitrile, nitromethane, formic acid, dichloromethane, etc., though not limited to these solvents. Solvents comprising tetrahydrofuran, dimethylformamide, hexane, or diethyl ether may also be used.

The reaction of the process may be carried out at a temperature in the range of-60°C to +150°C although a temperature of from 0°C to 100°C is preferred.

The ratio of fluorinating reagent to organic compound of formula 12,13,14 or 15 may be varied within wide limits although it is preferred that the molar ratio is in the range 0.5 to 10: 1, especially 1 to 3: 1.

When the fluorination reaction of the process is complete, the selectively fluorinated organic compounds, e. g. 3,4,5,6,7,8 and 9 may be isolated by addition of water to the cooled reaction followed by extraction of the selectively fluorinated organic compound into a suitable solvent followed by, for example, purification by distillation or column chromatography.

Embodiments of the present invention will now be described, by way of example only, with reference to the following examples.

Example 1: Preparation of 1-Fluoroadamantane 1-fluoroadamantane shown in scheme in Figure 4 was prepared as follows. A solution containing selectfluorTM (4.69g, 13 mmol) and adamantane (1. OOg, 7 mmol) in dry acetonitrile (100 cm3) was stirred at reflux temperature. After 3 h the reaction mixture was poured into water, neutralised (NaIIC03) and extracted three times using DCM. The combined dried (MgS04) organic extracts were evaporated to give a brown solid. Column chromatography on silica gel using 6: 1 cyclohexane-DCM was used to isolate 1- fluoroadamantane (0.23g, 30%, 73% conv.) as a white solid from this crude product; mp 256-258°C (Lit. 257-259°C); BF (376 Mhz) 128.8 (s); blS (400 Mhz) 1.69 (2H, m, 4-H), 1.95 (2 H, m, 2-H), 2.16 (1 H, s, 3-H); 6c (101 Mhz) 31.5 (d, 3Jc, : 9.6, C-3), 35.8 (d, 4ici 1.9, C 4), 42.7 (d, 2JCF 17, 1, C-2), 92.6 (d,'JCF 183.2, C-1); m/z (EI4) 154 (M+, 75%).

Example 2: Preparation of Fluorocyclohexane A solution containing SelectfluorTM (13.91 g, 39 mmol), cyclohexane (3.00 g, 36 mmol) and dry acetonitrile (130 cm3) was stirred and heated (65°C). After 26 h the reaction mixture was poured into water, neutralised (NaNCO3) and extracted with dichloromethane (3 x 50 ml). The combined, dried (MgS04) organic extracts were evaporated to give a colourless product (8.00 g) which contained fluorocyclohexane (0.77 g, 21%, 100% conv.).

Purification of the crude product by preparative scale GC gave an analytically pure sample of fluorocyclohexane as a colourless oil; bp 101-103°C (Lit., [Ashton, 1971 &num 109] 62°C/180mmHg) (Found: C, 69.5; H, 10.7, M+, 102.0845. C6H11F requires C, 70.53; H, 10.9%, M+, 102.0845); #F (376 MHz)-171.47 (br s); 8H (400 MHz) 1.30-1.75 (10 H, m, 2- H, 3-H and 4-H), 4.57 (1 H, dm, 2JHF 48.8, JHH 5c (100 MHz) 22.8 (d, 3JCF 7.7, <BR> <BR> <BR> <BR> C-3), 25.2 (d, 4JCF 1.5, C-4), 32.3 (d, 2JCF 18.7, C-2), 91.5 (d, Ucp 169.8, C-1) ; m/z (EI+) 102 (M+, 8%), 82 (40, M+-HF).

Example 3: Fluorination of trans-decalin A solution containing SelectfluorTM (24.85 g, 70 mmol), trans-decalin (5.38 g, 70 mmol) and dry acetonitrile (250 cm3) was stirred at reflux temperature. After 4.5 h the reaction mixture was worked up as above to give a brown liquid (4.37 g) which contained trans- fluorodecalin (2.21 g, 25%, 81% conv.) (31 area %), trans-decalin (65 area %) and, trace amounts of other products. Purification of the crude product by preparative scale GC gave an analytically pure sample of trans-fluorodecalin as an isomeric mixture of 2- fluoro (eq) decalin (isomer 3), 1-fluoro (eq) decalin (isomer 2), 2-fluoro (ax) decalin (isomer 4) and l-fluoro (ax) decalin (isomer 1) in the ratio of 1.36: 1.14: 2.24: 1: 00 respectively and, as <BR> <BR> <BR> <BR> a colourless oil (Found: C, 77.0; H, 11.1. C10H17F requires C, 76.9; H, 11.0%); #F (376 MHz)-167.97 (dd, 2JHF 49. 4,3 JI-IF 4.5, isomer 3),-177.34 (d, 2JHF 49. 3, isomer 2),-183.07 (tq, 2juif 47.8, 3JHF 10.2, isomer 4),-196.61 (mq, 2JHF 49.6, isomer 1); Sn (400 MHz) 0.60- 2.10 (113.97 H, m, CH2 and CH), 4.08 (1.16 H, dddd, 2JHIT 49.8,3JIIF 10.8,3JHF 9.9,3 JUIF 4.8, CHF-isomer 2), 4.47 (1.47 H, dtt, 2JHF 49.2,3JHF 10.8,3JHF 4. 8, CHF-isomer 3), 4.54 (1.00 H, ddt, 2JHF 49.2,3JHF 3.2,3JHF 2.0, CHF-isomer 1), 4.87 (2.40 H, d sept, 2JHF 48.4, 3JHF 2.0, CHF-isomer 4); 5c (101 MHz) 20.5 (s, CH2-isomer 1), 23.4 (s, CH2-isomer 1 or <BR> <BR> <BR> 2), 23.5 (s, CH2-isomer 1 or 2), 25.9 (s, CH2-isomer 2), 26.4 (d, 4JCF 0.7, CH2-isomer 3), 26.5 (s, CH2), 26.6 (s, CH2), 26.7 (s, CH2), 26.8 (s, CH2), 26.9 (s, CH2), 27.0 (s, CH2), 27.9 <BR> <BR> <BR> (s, CH2-isomer 4), 28.9 (d, 3JCF 2.7, CH2-isomer 2), 29.3 (d, 3JCF 2.3, CH2-isomer I), 31.1<BR> <BR> <BR> (d, 2JCF 21.3, CH2-isomer 4), 31.4 (d, 11.5, CH2-isomer 3), 31.7 (d, 2JCF 21.7, CH2-isomer 1), 32.8 (s, CH2-isomer 2), 33.1 (d, 2JCF 17.6, CH2-isomer 2), 33.2 (d, 12.7, CH2-isomer 2), 33.5 (s, CH2-isomer 1 or 4), 33.5 (s, CH2-isomer 1 or 4), 33.9 (s, CH2-isomer 4), 33.9 (d, 3JCF 2.3, CH2-isomer 4), 34.4 (s, CH2), 36.4 (s, CHR3-isomer 1), 36.9 (s, CHR3-isomer 4), 38.5 (d, 2JCF 21.4, CH2-isomer 4), 40.3 (d, 2JCF 16.4, CH2-isomer 2), 40.8 (d, 10.7, CHR3- <BR> <BR> <BR> isomer 2), 40.9 (d, 9.2, CHR3-isomer 3), 42.3 (d, 4JCF 1.9, CHR3-isomer 2), 42.7 (d, CHR3- isomer 4), 46.6 (d, 2JCF 19.3, CHR3-isomer 1), 48.8 (d, 2JCF 16.3, CHR3-isomer 3), 90.6 (d, <BR> <BR> <BR> IJcF 165.0, CHF-isomer 4), 92.6 (d, Ucp 170.4, CHF-isomer 3), 93.2 (d,'JCF 168.4, CHF-<BR> <BR> <BR> isomer 1), 96.7 (d, IJcF 171.4, CHF-isomer 2); mlz (EI+) 156 (M+, 82%), 136 (76, M+-HF), all isomers gave a similar result.

Isomer1Isomer 2Isomer 3Isomer 4 Example 4: Fluorination of cis-decalin A solution containing SelectfluorTM (13.85 g, 39 mmol), cis-decalin (3.00 g, 22 mmol) and dry acetonitrile (120 cm3) was stirred at reflux temperature. After 1.5 h the reaction mixture was worked up as before to give a yellow liquid (3.20 g) which contained cis-fluorodecalin (0.77 g, 30%, 75% conv.) (39 area %), cis-decalin (43 area %) and, trace amounts of other products. Purification of the crude product by preparative scale GC gave an analytically pure sample of cis-fluorodecalin as an isomeric mixture of l-fluoro (ax) decalin (isomer 1), 1- fluoro (eq) decalin (isomer 2), 2-fluoro (eq) decalin (isomer 3) and 2-fluoro (ax) decalin (isomer 4) in the ratio of 1.60: 1.40: 1. 30: 1: 00 not necessarily respectively and, as a colourless oil (Found: C, 77.0; H, 11.1. CloHl7F requires C, 76.9; H, 11.0%); 8p (376 MHz,-57°C)- 166.55 (d, 2JHF 47. 8),-173.43 (d, 2JHF 49.3),-179.08 (d, 2JHF 49.6),-183.92 (q, 2JHF 37.9) ; 8H (400 MHz,-57°C) 1.07-2.06 (16 H, m, CH and CH2), 4.45-4.84 (1 H, m, CHF); oc (101 MHz,-57°C) 18.0-42.0 (many s and m, CH and CH2), 90.5 (d, Ucp 171.7, CHF), 90.8 (d, 1JCF 165.5, CHF), 94.1 (d, IJCF 170.5, CHF), 94. (d, 1JCF 166.0, CHF); m/z (EI+) 156 (M+, 22%), 136 (86, M+-HF), all isomers gave a similar result.

Isomer1Isomer 2Isomer 3Isomer 4 Example 5: Fluorination of decane A solution containing SelectfluorTM (21.42 g, 61 mmol), decane (7.81 g, 55 mmol) and dry acetonitrile (210 cm3) was stirred and heated (82°C). After 18 h the reaction mixture was worked up as above to give a orange liquid (10.77 g) which contained fluorodecane (4.28 g, 58%, 84% conv.) (50 area %), decane (16 area %) and, small amounts of other unidentified products. Purification by preparative scale GC gave an isomeric mixture of 2-, 3-, 4-and 5- fluorodecane in the ratio of 2. 39: 1.27: 1.09: 1.00 not necassarily respectively and, as a colourless liquid (Found: M+-HF, 140.1565. CloH21F requires M+-HF, 140.1565); 8p (376 MHz)-172.46 (m, JHF 19.2),-180.38 (m, JHF 17.3),-180.71 (m, JHF 17. 2),-181.62 (m, JHF 18.8); on (400 MHz) 0.85-0.98 (5 H, m, CH2 and/or CH3), 1.24-1.70 (15 H, m, CH2 and/or CH3), (1.00 H, m, CHF); 5c (100 MHz) 9.4 (s, CH3), 9.42 (s, CH3), 13.9 (s, CH3), 14.0 (s, CH3), 14.1 (s, CH3), 18.4 (d, 3JCF 4.6, CH2), 21.0 (d, 2JCF 22.9, CH3), 22.6 (s, CH2), 22.7 (s, CH2), 24.8 (d, 3JCF 4.6, CH2), 25.1 (d, 3JCF 5.0, CH2), 27.3 (d, 3JCF 4.6, CH2), 28.1 (d, 2JCF 21.3, CH2), 29.2 (d, 3JCF 2.6, CH2), 29.2 (s, CH2), 29.5 (d, 4JCF 1.2, CH2), 29.7 (s, CH2), 31.7 (d, 3JCF 4.2, CH2), 31.8 (d, 3JCF 4.1, CH2), 31.9 (s, CH2), 34.7 (d, 2JCF 20.5, CH2), 34.9 (d, 2JCF 20.9, CH2), 35.1 (d, 2JCF 21.0, CH2), 35.2 (d, 2JCF 20.5, CH2), 36.9 (d, 2JCF 20. 6, CH2), 37.3 (d, 2JCF 21.0, CH2), 91.1 (d, Ucp 164.1, CHF), 94.4 (d, <BR> <BR> <BR> <BR> IJcF 166.4, CHF), 94.6 (d, 1 JCF 166.4, CHF), 95.8 (d,'JCF 166.1, CHF); m/z (EI+) 140 (M+-HF, 1 %), 111 (9), 97 (22), all isomers gave a similar result.

Example 6: Fluorination of Methyl valerate A mixture containing SelectfluorTM (13.42 g, 38 mmol), methyl valerate (4.00 g, 34 mmol) and dry acetonitrile (130 cm3) was stirred and heated (82°C). After 16 h the reaction mixture was worked up as above to give a colourless product (10.05 g) which contained methyl valerate (55 area %); methyl 4-fluorovalerate and methyl 3-fluorovalerate (0.94 g, 49%, 42% conv.) (32 area %) and, small amounts of other unidentified products. Purification by preparative scale GC gave a sample of methyl 4-fluorovalerate and methyl 3-fluorovalerate as an isomeric mixture in the ratio of 1.2: 1.0 respectively and, as a colourless oil (Found: M++NH4,152.1092. CeHnFC requires: M++NH4,152.1087); methyl 4-fluorovalerate 8F <BR> <BR> <BR> <BR> (376 MHz)-173.97 (m); 81-1 (400 MHz) 1.31 (3 H, d, 3JI-IH 6.4,5-H), 1.78-1.90 (2 H, m, 3- H), 2.40 (2 H, m, 2-H), 3.62 (3 H, s, OCH3), 4.62 (1 H, dm, 2JHF 49.2, 4-H) ; 8c (100 MHz) 20.8 (d, 2JCF 22.6, C-5), 29.6 (d, 3JCF 4.5, C-2), 31.9 (d, 2JCF 21.4, C-3), 51.6 (s, OCH3), 89.9 (d, IJcF 166.2, C-4), 173.5 (s, C-1); m/z (EI+) 114 (M+-HF, 8%), 103 (27), 83 (20), 74 (23); methyl 3-fluorovalerate Sp (376 MHz)-179.81 (m); aH (400 MHz) 0.98 (3 H, t, 3JllH 7.2,5-H), 1.65 (2 H, m, 4-H), 2.63 (2 H, m, 2-H), 3.65 (3 H, s, OCH3), 4.81 (1 I-I, dm, 2JE-IF 48.4,4-H); 8C (100 MHz) 9.0 (s, C-5), 27.8 (d, 2JCF 21.0, C-4), 39.8 (d, 2JCF 24.1, C-2), 51.8 (s, OCH3), 91.4 (d, IJcF 170.9, C-3), 174.3 (s, C-1); m/z (EI+) 114 (M+-HF, 8%), 103 (27), 83 (20), 74 (23).

Example 7: Fluorination of Methyl enanthate A mixture containing SelectfluorTM (13.66 g, 31 mmol), methyl enanthate (4.00 g, 28 mmol) and dry acetonitrile (140 cm3) was stirred and heated (82°C). After 16 h the reaction mixture was worked up as above to give a yellow product (4.68 g) which contained methyl enanthate (49 area %), methyl 3-, 4-, 5-and 6-fluoroenanthate (1.24 g, 48%, 57% conv.) (42 area %) and, small amounts of other unidentified products. Purification of the crude product by preparative scale GC gave an analytically pure sample of methyl 6-fluoroenanthate (A), methyl 5-fluoroenanthate (B), methyl 4-fluoroenanthate (C) and methyl 3-fluoroenanthate (D) in the ratio of 3.7: 1.3: 1.3: 1: 0 respectively and, as a colourless liquid (Found: C, 59.1; <BR> <BR> <BR> <BR> H, 9.3. C8H15F02 requires C, 59.2; H, 9. 3%); 8r (376 MHz)-173.14 (m, A),-180.08 (m, C),-182.8 (m, B),-183.62 (m, D); 8H (400 MHz) 0.80-1.00 (1 H, m, CH2 and/or CH3), 1.27- 1.65 (7 H, m, CH2 and/or CH3), 2.30-2.38 (3 H, m, CH2 and/or CH3), 3.67-6.68 (3 H, m, <BR> <BR> <BR> <BR> OCH3), 4.25-5.02 (1 H, m, CHF); 8C (100 MHz) 9.6 (d, JCF 4.9, CH3-B, C or D), 14.1 (s, CH3-B, C or D), 14.2 (s, CH3-B, C or D), 18.5 (s, CH2), 18.6 (s, CH2), 20.9 (d, JCF 4.1, <BR> <BR> <BR> <BR> CH2), 21.2 (d, 2JCF 22.9, CH3-A), 24.9 (d, Jcr 5.0, CH2), 27.2 (d, JCIX 4.2, CH2), 28.5 (d,<BR> <BR> <BR> <BR> <BR> <BR> 2JCF 22.6, CH2CHF), 29.9 (d, JCF 4.2, CH2), 30.5 (d, 2JCF 21.4, CH2CHF), 33.9 (s, CH2), 34.2 (d, 2JCF 21.0, CH2CHF), 34.8 (d, 2JCF 20.2, CH2CHF), 36.8 (d, 2JCF 20.6, CH2CHF- <BR> <BR> <BR> <BR> A), 37.4 (d, 2JCF 20.6, CH2CHF), 40.5 (d, 2JCF 24.0, CH2CHF), 51.7 (s, OCH3), 51.8 (s,<BR> <BR> <BR> <BR> <BR> <BR> OCH3), 51.8 (s, OCH3), 51.9 (s, OCH3), 90.6 (d, 1JCF 169.4, CHF-C), 90.7 (d, 1JCF 164.5,<BR> <BR> <BR> <BR> <BR> <BR> <BR> CHF-A), 92.4 (d, IJcF 167.9, CHF-D), 95.4 (d, IJCr 167.5, CHF-B), 173.9 (s, CO-D), 174.1 (s, CO-B), 174.3 (s, CO-A), 174.6 (s, CO-C); mlz (CI+, NH3) 180 (M+ + 18,100%), all isomers gave a similar result.

Example 8: Fluorination of 1-Chlorohexane A mixture containing SelectfluorTM (25. 96 g, 73 mmol), 1-chlorohexane (8.00 g, 67 mmol) and dry acetonitrile (260 cm3) was stirred and heated (82°C). After 16 h the reaction mixture was worked up as above to give a dark yellow product (8.24 g) which contained 1- chlorohexane (59 area %), 1-chloro-2-, 3-, 4-and 5-fluorohexane (2.75 g, 56%, 53% conv.) (37 area %) in the ratio of 1.0: 2.7: 5.2: 10.1 respectively; bF (188 MHz)-171.50 (m, 1- chloro-5-fluorohexane),-180.99 (m, 1-chloro-4-fluorohexane),-181.80 (m, 1-chloro-2- fluorohexane),-183.80 (m, 1-chloro-3-fluorohexane) and, small amounts of other unidentified products. Purification by preparative scale GC gave an analytically pure sample of 1-chloro-5-fluorohexane and 1-chloro-4-fluorohexane as an isomeric mixture and, as a <BR> <BR> <BR> <BR> colourless oil (Found: C, 51.8; H, 8.7. C6H12ClF requires C, 52.0; H, 8.7%); 6F (376 MHz)-<BR> <BR> <BR> <BR> <BR> 173.29 (m, 1-chloro-5-fluorohexane),-182.64 (m, 1-chloro-4-fluorohexane); 6H (400 MHz) 0.90-1.00 (4.7 H, m, CH2 and/or CH3), 1.29-2.10 (37.6 H, m, CH2 and/or CH3), 3.55 (11.4 H, m, CH2CI), 4.42 (1 H, dm, 2JHF 49.5, CHF-1-chloro-4-fluorohexane), 4.68 (3.7 H, dm, 2JHF 48.5, CHF-1-chloro-5-fluorohexane); 1-chloro-5-fluorohexane 8C (100 MHz) 21.0 (d, 2JCF 20.9, C-6), 22.5 (d, 3JCF 5.0, C-3), 32.3 (s, C-2), 36.1 (d, 2JCF 21. 0, C-4), 44.8 (s, C-l), 90.7 (d, 1JCF 164.4, C-5); m/z (EI+) no indicative peaks observed; I-chloro-4-fluorohexane 5c (100 MHz) 9.3 (d, 3JCF 6.4, C-6), 28.1 (d, 2JCF 21.0, C-3 or C-5), 28.3 (d, 3JCF 3.8, C-2), 32.0 (d, 2JCF 21.3, C-3 or C-5), 44.9 (s, C-l), 94.9 (d, ! Jcp 168.3, C-4); mlz (EI+) no indicative peaks observed.

Example 9: Fluorination of 1-Bromohexane A mixture containing SelectfluorTM (11.80 g, 33 mmol), 1-bromohexane (5.00 g, 30 mmol) and dry acetonitrile (120 cm3) was stirred and heated (82°C). After 16 h the reaction mixture was worked up as above to give a dark yellow product (7.93 g) which contained 1- bromohexane (69 area %), 1-bromo-3-, 4-and 5-fluorohexane (1.10 g, 75%, 30% conv.) (21 area %) in the ratio of 1.0: 1.8: 4.8 respectively; 8F (188 MHz)-172.34 (m, 1-bromo-5- fluorohexane),-181.74 (m, 1-bromo-4-fluorohexane),-185.00 (m, 1-bromo-3-fluorohexane) and, a large number of other unidentified products (10 area %). Purification by preparative scale GC gave an analytically pure sample of 1-bromo-5-fluorohexane and 1-bromo-4- fluorohexane as an isomeric mixture and, as a colourless oil (Found: C, 39.6; H, 6.7.

C6Hi2BrF requires: C, 39.4; H, 6.6%); 8p (376 MHz)-171.83 (m, 1-bromo-5-fluorohexane), -181.18 (m, 1-bromo-4-fluorohexane); on (400 MHz) 0.85-1.00 (3.5 H, m, CH2 and/or CH3), 1.29-2. 05 (28 H, m, CH2 and/or CH3), 3.42 (7 H, m, CH2Br), 4.43 (2.5 H, dm, 2JHF 49.2, CHF-1-bromo-5-fluorohexane), 4.66 (1 H, dm, 2JHF 48.8, CHF-1-bromo-4- <BR> <BR> <BR> <BR> fluorohexane); 1-bromo-5-fluorohexane 8C (100 MHz) 21.0 (d, 2JCF 22.8, C-6), 23.8 (d, 3JCF 4.6, C-3), 32.5 (s, C-2), 33.5 (s, C-1), 35.9 (d, 2JCF 20.6, C-4), 90.7 (d, 1JCF 164.9, C-5); m/z <BR> <BR> <BR> (El+) no indicative peaks observed; I-bromo-4-fluorohexane 8c (100 MHz) 9.3 (d, 3JCF 5. 7,<BR> <BR> <BR> <BR> <BR> <BR> C-6), 28.1 (d, 2JCF 21.0, C-3 or C-5), 28.4 (d, 3JCF 3.8, C-2), 33.2 (d, 2JCF 20.9, C-3 or C-5),<BR> <BR> <BR> <BR> <BR> 33.6 (s, C-1), 94.8 (d, IJCF 168.3, C-4); m/z (El-) no indicative peaks observed.