Reactions involving fluoride ion. Part 39. Reactions of perfluorinated dienes with oxygen and sulphur nucleophiles

摘要

J. CHEM. SOC. PERKIN TRANS. 1 1994 31 19 Reactions Involving Fluoride Ion. Part 39.’Reactions of Perfluorinated Dienes with Oxygen and Sulphur Nucleophiles Mark W. Briscoe, Richard D. Chambers,* Steven J. Mullins, Takayuki Nakamura and Julian F. S. VaughanDepartment of Chemistry, University Science Laboratories, South Road, Durham DHI 3LE, UK The order of reactivity of perfluorinated dienes towards methanol is 3 2 % 1 and the process is activated by release of angle strain. The diene 1 is hydrolysed to give perfluorotetramethyl-furan and the corresponding thiophene, is obtained by an analogous process using K,S. Hydrolysis of compounds 2 and 3 yields diketones that are strong acids. Reactions of phenols and thiophenols with 1 give aryl ethers and sulfides and difunctional nucleophiles react with 1to give potential polymer precursors.In the preceding paper of this series we described efficient syntheses of the fluorinated dienes 1-3, from oligomers which were themselves obtained from interaction of fluoride ion with some readily available fluorinated alkenes and cycloalkenes. Thus, a significant objective is achieved, which is to create simple methodology for obtaining chemically more sophisti- cated systems fromsimple fluorinated starting materials. This is crucially important to the area of polyfluorlnated compounds that are wholly ‘man-made’ molecules. In this paper we describe the reactions of these new interesting electron-deficient dienes 1-3 with some oxygen and sulphur nucleophiles. Reactions with methanol show a considerable range in reactivity; the diene 3 reacts exothermically with neutral methanol giving the bis-dimethyl ether 6.Fluorinated alkenes are generally reactive to nucleophiles but this remarkable level of reactivity is usually associated with perfluoroi~obutene,~ and it is comparatively rare that fluorinated systems will react with neutral methan01.~ 1 X,Y=F 2 X,Y=F 3 X=F 4 X=F,Y=OMe 5 X=F,Y=OMe 6 X=OMe 7 X.Y=OMe 8 X,Y=OMe Perfluorobicyclopentenyl 2 reacted with neutral methanol but only over a period of days, giving 5 and 8, while the diene 1 required addition of base to promote reaction with methanol, giving 4 and 7.Electronic effects are broadly equivalent for each of the dienes and, therefore, the dramatic difference in reactivity 3 2 9 1 is best accounted for on the basis of angle strain.Obviously, angle strain is relieved in the process 3+9, and the dramatic change in reactivity in the series 1-3 provides a nice illustration of this effect on reactivity (Scheme 1). d FU 3 9 Scheme 1 Hydrolysis is more complicated in that the diene 1 gavea product of cyclisation (Scheme 2), perfluorotetramethylfuran 11 and, indeed, this process occurs so readily in the presence of base that nucleophilic reactions on 1 frequently give 11 as an impurity in the Product unless moisture is most rigorously excluded from the solvent. F3C CF, 1 F*cF3 -F ‘KcF3 F3C 0 10 F3C -0 1 .. Scheme 2 Hydrolysis of the diene 1 The process proceeds by initial vinylic displacement of fluorine and then the intermediate ion 10 clearly undergoes a rapid electrocyclic process, accompanied by elimination of fluoride ion to give 11.The process is quantitative and represents a more direct route to the furan derivative 11 than previous procedures. Analogous formation of the corre-sponding perfluorotetramethylthiophene 12 was less efficient but reaction of 1 with either potassium sulphide or thiourea gave 12. 12 Scheme 3 Reagents and conditions: i, K,S, DMF, room temp. (72%); ii, (NH,),CS, MeCN, reflux (51%) Reactions of the cyclic dienes 2 and 3 proceeded in a different manner. Hydrolysis of 2 and 3 in aqueous acetonitrile gave the corresponding diketones 14 and 13, and the mechanism of formation of 13 is indicated in Scheme 4.@-y-*OH 0 ’3 0 Scheme 4 Hydrolysis of the diene 3. Reagents and conditions: i, MeCN, room temp. 3 120 J. CHEM. SOC. PERKIN TRANS. 1 1994 The structure of 13 was derived partly from the observation of a resonance in the "F NMR that could be attributed to CF=C and 3 resonances, of equal intensity, attributable to CF,. Hydrolysis of 2 followed a similar mechanism to give the analogous product 14. 0 0 2 14 I 14* OH mixture of E,Z and Z,Z isomers of the diene 1, then these reactions are obviously subject to thermodynamic control of stereochemistry, with the bulky trifluoromethyl groups dominating the outcome. The product 25 reacted further with sodium methoxide, to give compound 26, and this demonstrates 0 that these intermediates could be used for a variety of block co- @ridpolymer syntheses for systems containing trifluoromethyl Scheme 5 Reagents and conditions: i, H,O, MeCN, room temp.Fluorinated diketones frequently exist principally in the enol form, e.g. hexafluoroacetylacetone,6 and this is probably the case for both 13 and 14. However, these compounds are very strong acids (see Fig. I), and pKa values are comparable to that of monofluoroacetic acid, although they do not approach that of the pseudo-aromatic compound squaric acid. OH OH pK, 2.30 2.37 2.59 4.75 Fig. 1 Indeed, we expected further loss of fluorine from 13 and 14 with base but, instead, neutralisation gave salts that were quite stable and could be isolated.The fact that cyclisation, analo- gous to that shown in Scheme 2, does not occur is most obviously attributable to the significant strain associated with the furan derivatives that would be obtained from 2 and 3, analogous to 11, obtained from 1. Reactions of the dienes 1 and 2 with phenol and thiophenol proceeded in an analogous manner and various mono-15a-d and di-substitution, 16a-c, 19 and 18a-q products were obtained (see Experimental section). CF3 CF3 CF3 CF3 '#Oph pho#OI'h CF3 CF3 CF3 CF3 15 16 OPh 17 18 These dienes are interesting monomers for polymerisation and we have made potential polymer precursors by reaction of the diene 1 with the difunctional derivatives 19-21.Reaction of the diene 1 with hydroquinone 19 and di- functional systems 20 and 21, gave the disubstituted derivatives 23,24 and 25, respectively (see Experimental section). It is interesting to note that the only discernible isomers of these di-substituted products involved the all-trans relative arrangements of trifluoromethyl groups. Since we begin with a groups. Experimental 'H NMR spectra were recorded on a Bruker AC250 spectrometer operating at 250.13 MHz or a Varian VXR4OOS spectrometer operating at 399.95 MHz. "F NMR spectra were recorded on the Bruker AC250 spectrometer operating at 235.34 MHz or on the Varian VXR4OOS spectrometer operating at 376.29 MHz. I3C NMR spectra were recorded on the Varian VXR400S spectrometer operating at 100.58 MHz.All spectra were recorded with tetramethylsilane and fluorotrichloro-methane as internal references. J Values are given in Hz. GLC Mass spectra were recorded on a VG 7070E spectrometer linked to a Hewlett Packard 5790A gas chromatograph fitted with a 25 m cross-linked methyl silicone capillary column. All mass spectra were generated by electron impact. Caution: The dienes 1,2and 3 should be assumed to be toxic. Reaction of the Diene 1 with Methano/.-A mixture con- taining the diene 1 (2.0 g, 5.5 mmol), methanol (0.7 g, 22.2 mmol), sodium carbonate (0.9 g, 8.5 mmol), and acetonitrile (2 cm3) was stirred at room temperature for 7 d, after which volatile material was transferred in vacua to a cold trap. The lower layer (1.4 g) was removed and shown by GLC to contain two products, which were separated by preparative scale GLC (column DNP, 110 "C), and identified as (1) (Z,Z)-and (E,Z)-2-methoxy-3,4-bis(trrJiuoromethyl)per~uorohexa-2,4-diene4a, b (90.2%).For the mixture (Found: C, 28.8; H, 0.7; F, 65.9. C,H,F,,O requires C, 28.9; H, 0.8; F, 66.0%); vma,/cm-' 1750w (W),1710w (C=C), 1385s (C-F) and 1360-1 110s (C-F); m/z 374 (M', 8%); for 4a 6,(250 MHz; CDCl,) 3.9 (s, OCH,); 6,(235 MHz; CDCl,) -61.1 (3 F, s, l-CF,), -61.7 (3 F, d, J4a,5 17.0, 4a-CF3), -64.1 (3 F, s, 3a-CF3), -69.1 (3 F, s, 6-CF3) and -106.5 (1 F, m, 5-CF); for 4b6,(250 MHz; CDCI,) 3.8 (s, OCH,); 6,(235 MHz; CDCl,) -56.8 (3 F, 9, J1,3a 11.8, l-CF,), -61.5 (3 F, d, J4a,516.9, 4a-CF3), -64.1 (3 F, s, 3a-CF3), -69.9 (3 F, d, J6,5,6-CF3), -109.2 (1 F, m, 5-CF) and (2) (E,E)-, (E,Z)- and (Z,Z)-2,5-dimethoxy-3,4-bis(trzJiuoromethy/)-perJiuorohexa-2,4-diene7a, b, c (9.8%).For the mixture (Found: C,30.0;H,0.7;F,58.9.Cl,H,Fl,0,requiresC,31.1;H,1.55;F, 59.1%); vma,/cm-' 17 590w (C=C), 1710w (M),1690w (M) and 1490-1 080s (C-F); m/z 386 (M +,20%); for 8a 6,(250 MHz; CDCl,) 3.8 (s, OCH,); 6,(235 MHz; CDCl,) -57.2 (6 F, m, 3a- and 4a-CF3), -64.3 (6 F, q, J3a,l11.6, 1-and 6-CF3); for 7b, c SH(250 MHz; CDCl,) 3.8 (s, OCH,); 6,(235 MHz; CDCl,) -61.3 and 61.1 (1 F, s, 3a- and 4a-CF3) and -64.0 and 64.9 (1 F, s, 1-and 6-CF3). Reaction of the Diene 2 with Methano/.-The diene 2 (2.0 g, 5.2 mmol) and methanol (0.80 g, 25.0 mmol) were mixed at room temperature to give an immediate exothermic reaction.J. CHEM. SOC. PERKIN TRANS. I 1994 3a 6 3a 6 CF3 CF3 9 4a 4a 4a 4b 3a 3a6 3a.~ 6-CF3 OMe CF3 CF3 CF3 CF3 F3'++lF3 F3'++OMe Me0 CF3 Me0 CF3 bF3 kF3 4a 4a 1 4a 7a 7b 7C The mixture was stirred and, after 48 h, a sample from the homogenous liquid was taken and shown by GLC to contain one product, which was identified as 2-methoxyperfluoro- 1,l'- bicyclopent-l-enyl5(Found:C, 33.4; H, 0.8; F, 57.9. C, 1H3F130 requires C, 33.2; H, 0.8; F, 62.1); v,,,/cm-' 1690m(W),1660m (C=C), 1380s (C-F), 1320m (C-F), 1280m (C-F), 1210m (C-F), 1180s (C-F) and 1160s (C-F); 6,(250 MHz; CDCl,) 4.2 (s, OCH,); 6,(235 MHz; CDCl,) -105.6 (2 F, s, 5-CF2), -107.8 (2 F, s, 5'-CF2), -113.0 (2 F, s, 3-CF2),-114.4 (1 F, m, 2'-CF), -119.5 (2 F, d, J6.7 14.0, 3'-CF,), -129.7 (2 F, S, 4-CF,), -130.5(2 F, s, 4'-CF,); m/z 398 (M', 100%).The reaction was allowed to continue for 10 d, after which solvent was removed to yield a crystalline white solid.This was purified by vacuum sublimation and identified as 2,2'-dimethoxyperfluoro-1,l '-bi- cyclopent-I-enyf 8, m.p. 54 "C (Found: C, 35.0; H, 1.2; F, 55.7. C,,F,,H,O, requiresc, 35.1; H, 1.5; F, 55.6%); v,,,/cm-l 1690 (GC), 1640m (C==C),1350s (C-F), 1245s (C-F), 1205m (C-F), 1130 (C-F) and 1115s (C-F); 6,(250 MHz; CDCl,) 4.1 (s, OCH,); 6,(235 MHz; CDCl,) -106.5 (1 F, s, 5-CF2), -115.6 (1 F,s, 3-CF2)and -131.0(1 F,s,4-CF2);m/z4l0(M+, 100%). MeO 4v33 :q-bs4' 2 OMe OMe 5 8 Reaction of the Diene 3 with Methanol.-Addition of the diene 3 (1.27 g, 4.4 mmol) to methanol (0.64 g, 20.0 mmol) gave an immediate exothermic reaction, with the formation of a white solid within 1 h.Solvent was then removed, and the residue sublimed in vacuo to give a white solid which was identified as 2,2-dimethoxyperfluoro- 1,l '-bicyclobut- 1-enyl 6 (1.00 g, 7373, m.p. 52°C (Found: C, 38.5, H, 1.9; F, 49.4. CloH,F,O, requires C, 38.7; H, 1.94; F, 49.0); v,,x/cm-l 1640s (C=C), 1380s (C-F), 1295s (C-F), 1120s (C-F), 1090m (C-F); 6,(250 MHz; CDCl,) 4.1 (s, OCH,); 6,(235 MHz; CDCl,) -11 1.7 (4 F, m, 4-CF2) and -114.7 (4 F, m, 3-CF2); m/z 310 (M + ,76%). OMe 6 Per-uorotetramethyljk-an 11.-A mixture containing the diene 1 (3.0 g, 8.3 mmol), water (0.2 g, 11.1 mmol), potassium carbonate (2.3 g, 16.7 mmol) and acetonitrile (20 cm3) was stirred at room temperature for 14 d.Volatile material was transferred in vacuo to a cold trap and more water (20 cm3) was 3121 added to it. The lower layer was removed and purified by distillation to yield the title compound 11(2.3 g, 5473, b.p. 101-103 "C (lit.,5 104-105 "C); vm,,/cm-l 1420w (W)and 1300s-1200s (C-F); 6,(235 MHz; CDCl,) -57.62 (1 F, m, CF,) and -62.40 (1 F, m, CF,); m/z 340 (M+, 44%) and 321 (100). Per-uorotetramethylthiophene 12.-A mixture containing the diene 1 (10.0 g, 27.6 mmol), potassium sulphide (4.5 g, 40.9 mmol) and DMF (25 cm3) was stirred at room temperature for 14 d. Volatile material was transferred in vacuo to a cold trap and water (25 cm3) was added to it.The lower layer was removed and purified by distillation to yield the title compound 12 (3.7 g, 38%), b.p. 134-135 "C (lit.,' 134-135 "C); v,,,/cm-' 1240s-1200s (C-F); 6,(235 MHz; CDCl,) -54.12 (1 F, m, CF,) and -56.00 (1 F, m, CF,); m/z 356 (M+, 81%) and 337 (100). Reaction of the Diene 1 with Thiourea.-A mixture contain- ing the diene 1 (2.0 g, 5.5 mmol), thiourea (0.5 g, 6.6 mmol) and acetonitrile (20 cm3) was heated under reflux for 16 h. Volatile material was transferred in vacuo to a cold trap and water (30 cm3) was added to it. The lower layer was removed and purified by distillation to give perfluorotetramethylthiophene 12 (1.O g, 51%), which was identified by comparison of the 19FNMR spectrum with that of an authentic sample (see earlier).Reaction of the Diene 3 with Water.-A mixture of the diene 3 (1.15 g, 4.0 mmol), acetonitrile (7 cm3) and distilled water (1.33 g, 74.0 mmol), was stirred at room temperature for 1 d, after which the solvent was removed. The residual solid sublimed in vacuo, to give a white hygroscopic solid which was identified as 4,4-di~7uoro-3-hydroxy-2-(perfluorocyclobut-1-enyl)but-2-enone 13 (0.80 g, 76%) (Found: C, 36.3; H, 0.8; F, 53.2. ClOHFllO, requires C, 36.6; H, 0.4; F, 53.8%); vmax/cm-l 3450w (OH), 1800w (W),1650s (GO)and 1410-1110s (C-F); 6,(376 MHz; CD,CN) -102.8 (1 F, t, 1-CF), -113.4 (2 F, br s, 4-CF,), -115.4 (2 F, 3-CF2) and -117.5 (2 F, 2-CF2); m/z 262 (M+, 14%).OH 0 13 NB: Proton exchanges with deuterium Reaction of the Diene 2 with Water.-A mixture of the diene 2 (0.70 g, 1.8 mmol), distilled water (1.05 g, 58.3 mmol) and acetonitrile (7 cm3) was stirred at room temperature for 3 d, after which solvent was removed. The residue was sublimed in vacuo, to give a white solid which was identified as tetrafluoro-3-hydroxy-2-(perJtuorocyclopent-1-enyl)cyclopent-2-enone 14 (0.50 g, 77%) (Found: C, 33.0; H, 0.3; F, 53.0. CloHF,,O, requires C, 32.5; H, 0.3; F, 53.7%); v,,,/cm 3450w (OH), 1740w (C=C), 1600s (C=O), 1350m (C-F) and 1210-1090s (C-F); 6,(376 MHz; CD3CN) -107.9 (2 F, d, JFF 10.8, 4-CF,), -ll5.1(1 F,m, 1-CF), -120.4(2F,d,JF,14.4,2-CF,), -125.2 3122 J. CHEM.SOC. PERKIN TRANS. 1 1994 (4 F, s, 5-CF2) and -131.9 (2 F, br s, 3-CF2); m/z 362 (M+, (3.3 g, 47%) which was shown to be a mixture (5 :4 :1) of (Z,Z)-, 14%). (E,Z)-and (E,E)-2,5-diphenoxy(3,4-bis(tr@uoromethyl)per-0 fluorohexa-2,4-diene 16ax. For the mixture (Found: C, 47.0; H, 2.0; F, 44.2. C,,H,,F,,0, requires C, 47.1; H, 2.0; F, 44.779; v,,,/cm-' 3020w (Ar-H), 1660m (Ar), 1600s (Ar), 1490 (Ar) and 136Ovs-114Ovs (C-F); m/z 510 (M', 10%); for 16a6,(250 MHz; CDCl,) 6.95 (2 H, m, 2'-, 2"-, 6'- and 6"-ArH), 7.10 (1 H, m, 4'- 14 OH and 4"-ArH) and 7.29 (2 H, m, 3'-, 3"-, 5'- and 5"-ArH); 6,(235 NB: Proton exchanges with deuterium MHz; CDCl,) -60.25 (1 F, q, J,,,, 2.3, 3a- and 4a-CF,), -,,,J,61.80 (1 F, q, 1.9, 1-and 6-CF3); for 16b 6,(250 MHz; Reaction of the Diene 1 with Phenol.-A mixture containing the diene 1 (5.0 g, 13.8 mmol), phenol (1.9 g, 20.2 mmol), dry potassium fluoride (4.8 g, 82.8 mmol) and acetonitrile (75 cm3) was stirred at room temperature for 7 d.The resulting mixture was poured into water (200 cm3) and the organic products were extracted into diethyl ether and the extract dried (MgSO,), filtered and evaporated. The more volatile components were separated by distillation (52-54 "C, 10 mmHg) to give a colourless oil (2.8 g, 46%) which was shown to be a mixture (38 :6 :5 :1) of (Z,Z)-, (Z,E)-, (E,E)- and (E,Z)-2-phenoxy-3,4- bis(tr@uoromethyl)perJEuorohexa-2,4-diene15a-d. For the mix- ture (Found: C, 38.7; H, 1.1; F, 56.9. C,,H5F,,0 requires C, 38.55; H, 1.2; F, 56.6%); v,,,/cm-' 3040w (ArH), 1710w (C=C), 1660m (Ar), 1600m (Ar), 1490m (Ar), 1380 (C-F) and 1290s- 1160s (C-F); m/z 436 (M', 22%); for 15a 6,(250 MHz; CDCl,) 6.89 (2 H, m, 2'- and 6'-ArH), 7.09 (1 H, m, 4'-ArH) and 7.25 (2 H, m, 3'- and 5'-ArH); 6,(235 MHz; CDCl,) -61.10 (3 F, s, 1-CF,), -61.12 (3 F, d, J4a,52O.3,4a-CF3), -62.31 (3 F, q, J,,,, 1.9, 3a-CF3), -69.59 (3 F, d, J6.5 4.9 Of 9, J6,3, 1.9 6-CF,), -105.19 (1 F, q, J5,,,15.5 of q, J5,68.1, 5-CF); for 15b6,(250 MHz; CDCl,) 6.82 (2 H, m, 2'- and 6'-ArH), 7.1 1 (1 H, m, 4'- ArH) and 7.27 (2 H, m, 3'- and 5'-ArH); 6,(235 MHz; CDCl,) -60.48 (3 F, d, J4a,515.4, 4a-CF3), -60.99 (3 F, s, I-CF,), -62.70 (3 F, q, J3,,' 11.9, 3a-CF3), -70.49 (3 F, d, J6.5 8.6,6-CF3), -107.08(1 F, q, J5,,,14.7ofq, J5,68.7,5-CF); for 1%6,(250 MHz; CDCl,) 6.89 (2 H, m, 2'- and 6'-ArH), 7.07 (1 H, m, 4'-ArH) and 7.26 (2 H, m, 3'- and 5'-ArH); 6,(235 MHz; CDCl,) -57.21 (3 F,d, J4,,5 10.4ofq, J4,,6 10.4ofq, J4,,3,2.6, 4a-CF3), -58.29 (3 F, q, J1.3, 11.7 of q, J1.4, 1.9, I-CF,), -63.39(3 F, S, 3a-CF3), -69.23 (3 F,q,J6,3, 10.7ofd,J6,, 7.7, 6-CF3), -101.33 (1 F, m, 5-CF); for 15d 6,(250 MHz; CDCl,) 6.91 (2 H, m, 2'- and 6'-ArH), 7.06 (1 H, m, 4'-ArH) and 7:23 (2 H, m, 3'- and 5'-ArH); 6,(235 MHz; CDCl,) -56.94 (3 F, d, 10.7ofq,J4a,6J4a,5 10.7ofq, J4,,,,2.9,4a-CF,), -58.29(3 F,s, I-CF,), -58.33 (3 F, 9, J3,,12.5,3a-CF3), -69.11 (3 F,q, J6,4, 10.5 of d, J6,57.5, 6-CF3) and -102.49 (1 F, m, 5-CF).3a6 3a6 Y 1 4a 3, 15a 15b 3a 3a 3, 1 4a s 1Sc 15d The remaining solid was purified by sublimation followed by recrystallisation from diethyl ether-hexane to give a waxy solid CDCl,) 6.77 (2 H, m, 2'- and 6'- or 2"- and 6"-ArH), 6.92 (2 H, m, 2'- and 6'- or 2"-and 6"-ArH), 7.12 (1 H, m, 4'- or 4"-ArH), 7.15 (1 H, m, 4'- or 4"-ArH) and 7.27 (4 H, m, 3'-, 3"-, 5'- and 5"- ArH); 6,(235 MHz; CDCl,) -57.15 (1 F, q, J3a,l10.9 of q, J3a,6 2.3, 3a-CF3), -59.56 (1 F, s, 4a-CF3), -62.04 (3 F, q, J1,,, 12.0, I-CF,) and -63.34 (3 F, 9, J6,3a 3.0, 6-CF3); for 16~ 6,(250 MHz; CDCl,) 6.87 (2 H, m, 2'-, 2"-, 6'- and 6"-ArH), 7.02 (1 H, m, 4'- and 4"-ArH) and 7.24 (2 H, m, 3'-, 3"-, 5'-and 5"-ArH); 6,(235 MHz; CDCl,) 56.43 (1 F, q, J3a,l1 1.3, 3a- and 4a-CF3), -62.31 (1 F, q, J1.3, 12.0, 1-and 6-CF3).3a R 3" 3 1 4a 16a I-w 4's($ 2 3' 16b 3" Y 16C Reaction of the Diene 2 with Phenol.-A mixture containing the diene 2 (1.0 g, 2.6 mmol), phenol (0.4 g, 4.3 mmol), dry potassium fluoride (1 .O g, 17.2 mmol) and acetonitrile (20 cm3) was stirred at room temperature for 7 d. The product was poured into water (100 cm3) and the organic components were extracted into diethyl ether, dried (MgSO,), filtered and evaporated. Sublimation of the residue gave 2,2'-diphenoxy- perfiuoro- 1,l '-bicyclopent- 1 -enyll7 (0.8 g, 58%), m.p. 79-82 "C (Found: C, 49.8; H, 2.1; F, 43.1. C22Hl,F1202 requiresc, 49.5; H, 1.9; F, 42.7%); vmax/cm-l 3020w (ArH), 1640m (Ar), 1590m (Ar), 1400m-980m (C-F); 6,(250 MHz; CDCl,) 7.25 (m, ArH); 6,(235 MHz; CDCl,) -106.90 (1 F, S, CF,), -116.93 (1 F, S, CF,) and -131.13 (1 F, s, CF,); m/z 572 (M+, 13%).Reaction of the Diene 1with Thiophend-Thiophenol(O.9 g, 8.2 mmol) was slowly added to a stirred suspension of sodium hydride (0.2 g, 8.3 mmol) in DMF (20 cm3), and the solution was left at room temperature for 30 min. The diene 1(2.0 g, 5.5 J. CHEM. SOC. PERKIN TRANS. 1 1994 mmol) was then added to the mixture which was then stirred for 2 h. The resulting mixture was poured into slightly alkaline water (100 cm3) and the organic products were extracted into diethyl ether and the extracts dried (MgSO,) and filtered. The ether was removed from the filtrate by distillation and the residual solid was first sublimed and then recrystallised from acetone to give a solid (1.3 g, 59%) which was shown to be a mixture (9 :8 :3) of (E, Z)-, (Z, Z)-and (E,E)-2,5-diphenyl-sulfanyl-3,4-bis(trlJuoromethyl)perJuorohexa-2,4-diene18ac For themixture(Found: C, 44.0; H, 2.2; F,41.5; S, 12.7.C,,H,,-F,,S, requires C, 44.3; H, 1.9; F, 42.0; S, 113%); v,,,/cm-' 3010w (ArH), 159Ow (Ar), 1490w (Ar), 1400w (Ar) and 1300m-1160s (C-F); m/z 433 (M+,30%); for 18a6,(250 MHz; CDCl,) 7.22 (1 H, m, 4'-or 4"-ArH), 7.23 (1 H, m, 4'-or 4"-ArH), 7.30 (2 H, m, 3'-and 5'-or 3" and 5"-ArH), 7.37 (2 H, m, 3'-and 5'-or 3" and 5"-ArH), 7.49 (2 H, m, 2'-and 6'-or 2"-and 6"-ArH) and 7.50 (2 H, m, 2'-and 6'-or 2"-and 6"-ArH); 6,(235 MHz; CDCl,) -56.43 (1 F, q, J1.3, 14.3, I-CF,), -56.57 (1 F, s, 4a-CF,), -57.31 (1 F,q, J3a,l13.6ofq, J3,,64.20fq, J,,,,, 1.6, 3a-CF,) and -57.75 (1 F, q, J6,3a4.1, 6-CF3); for 18b 6,(250 MHz; CDCl,) 7.21 (1 H, m, 4'-and 4"-ArH), 7.36 (2 H, m, 3'-, 3"-, 5'-and 5"-ArH) and 7.46 (2 H, m, 2'-, 2"-, 6'-and 6"-ArH); 6,(235 MHz; CDC1,) -57.27 (1 F, pseudo-sept, J3a,l+4a 2.4, 3a-and 4a-CF3), -57.88 (1 F, pseudo-sept, J1.3+4a 2.4, 1-and 6-CF3); for 18c 6,(250 MHz; CDCl,) 7.24 (1 H, m, 4'-and 4"-ArH), 7.40 (2 H, m, 3'-, 3"-, 5'-and 5"-ArH) and 7.50 (2 H, m, 2'-, 2"-, 6'-and 6"-ArH); 6,(235 MHz; CDCl,) -56.1 1 (1 F, q, J1,3, 13.3, 1-and 6-CF3), -56.45 (1 F, q, J3,,1 13.3,3a-and 4a-CF3).8 18a 3' 1 4a 18b 8 1Bc Reaction of the Diene 1 with Benzene-l,4-diol19.-Benzene-1,4-diol19 (0.3 g, 2.7 mmol) in diethyl ether (10 cm3)was added dropwise to a stirred mixture containing the diene 1 (2.0 g, 5.5 mmol), dry caesium carbonate (4.0 g, 12.3 mmol) and diethyl ether (30 cm3).After 4.5 d at room temperature, the solvent was removed, and molecular distillation of the residue (30 "C, 0.8 mmHg) gave a colourless liquid which crystallised at room temperature, and was identified as a 28: 13:5: 2 mixture of (Z, 2)-, (Z,E)-, (E,E)-, and (E, Z)-2-(4-hydroxyphenoxy)-3,4-bis(trcJ7~0r0methyr)per-uorohexa-2,4-diene22ad (0.4 g, 32.5%).For the mixture (Found: C, 37.0; H, 1.2. C14H5F1302requires 3123 C, 37.2; H, 1.1%); v,,,/cm-' 1710w (W),1670w (Ar), 1505m (Ar), 1360m (C-F) and 1300-1070s (C-F); 6,[400 MHz; (CD,),CO] 7.36 (2 H, AB, J 8.8, 2'-ArH), 7.32 (2 H, AB, J 8.8 3'-ArH) and 2.84 (br s, OH); m/z452 (M+,773,451 (M+-l);for 22a dF[376 MHz; (CD,),CO] -61.12 (3 F, s, 3a-CF3), -62.34 (3 F, s, 1-CF,), -61.26 (3 F, d, J4a,516.2, 4a-CF3), -69.51 (3 F, s, 6-CF3) and -104.76(1 F, m, 5-CF); for 22b 6,[376 MHz; (CD,),CO] -58.14 (3 F, m, 3a-CF3), -63.50 (3 F, q, J1,3a 6.8, 1-CF,), -60.56(3 F, d, J4a,515.4,4a-CF,), -70.54(3 F, d, J6,5 7.2, 6-CF3) and -106.41(1 F, m, 5-CF); for 22c 6,[376 MHz; (CD,),CO] -57.33 (3 F, q, J3a,l 9.0, 3a-CF3), -61.00 (3 F, s, I-CF,), -63.50 (3 F, S, 4a-CF3), -69.25 (3 F, d, J6.5 10.5 Of 9, J6,,, 2.1, 6-CF3) and -100.03 (1 F, m, 5-CF); for 22d 6,[376 MHz; (CD,),CO] -56.99 (3 F, m, 3a-CF3), -63.30 (3 F, m, 1-3.8 of q, J4a,3aCF,), -64.17 (3 F, d, J4a,5 l.9,4a-CF3), -69.25 (3 F, s, 6-CF3) and -101.12(1 F, m, 5-CF).63a 63a CF3 CF3 1 CF3 CF3 CF3 0 4a 1 22a 22b -OH OH I CF3 1 5&F CF3 F3C*cF3 F3C+'-0,6 CF3 CF3 '-.. 4a 1 -WH 'OH 22d22C The remaining solid was purified by sublimation (50 "C, 0.8 mmHg) to give a white material, which was shown to be one product by NMR, and identified as p-phenylenedioxy-2,2'-bis[3,4-bis( trlJ~0r0methyl)perJu0rohexa-2,4-diene]23 (1.25 g, 58%) (Found: C, 33.0; H, 0.5. C,,H4F,60, requires C, 33.25; H, 0.5%); v,,,/cm-' 171Ow (W),1665w (Ar), 1505m (Ar), I360m (CF) and 1330-1050s (CF); 6,(400 MHz; CDC1,) 7.02 (s, 2'-and 3"-ArH); 6,(376 MHz; CDCl,) -60.52 (6 F, d, J4a,516.2, 4a-CF3), -60.58 (6 F, s, 3a-CF3), -61.85 (6 F, s, I-CF,), -68.93 (6 F, d, J6,54.1, CF3-6) and -104.16(2 F, q, J5,4a of q, J5,67.5, CF-5); m/z 794 (M+,64%). F CF3 CF3 CF3 CF3 23 Reaction of the Diene 1 with Biphenyl-4,4-diol 22.-A solution of biphenyl-4,4'-diol 20 (0.77 g, 4.1 mmol), in diethyl ether (5 cm3) and acetone (5 cm3), was added dropwise to a mixture of the diene 1 (3.00 g, 8.3 mmol), caesium carbonate (5.400g, 16.6mmol) and acetonitrile (30cm3).After the mixture had been stirred for 72 h at room temperature, the resulting solid was filtered off, and the filtrate evaporated.The residue was dissolved in CH,Cl, (30 cm3) and the solution dried (MgSO,) and evaporated under reduced pressure; the residue was sublimed in vacuo (80°C, 0.05 mmHg) to give a white solid which was identified as (biphenyl-4,4'-diyldioxy)-2,2'-bis[3,4-bis(trifiuoromethyl)perJuorohexa-2,4-diene]24 (2.8 g, 78%)(Found: c, 38.8; H, 0.85.C28M8F2602requires c, 38.6; H, 0.9%); v,,,/cm~' 1705w (C=C), 1665w (Ar), 1607w (Ar), 1495m 3124 (AR), 1360111 (CF) and 1330-1090s (CF); 6,(400 MHz; CDCl,) 7.06 (4 H, AB, J 8.6,3'-ArH) and 7.55 (4 H, AB, J 8.6,2'-ArH); 6,(376 MHz; CDCl,) -60.41 (6 F, d, J6,523.7, 4a-CF3), -60.51 (F, s, 3a-CF3), -61.75 (6 F, s, l-CF,), -68.91 (6 F, s, 6-CF3) and -104.26 (2 F, m, 5-CF); m/z 870 (M', 63%). 6 3a CF3 CF3 CF3 CF3 4a 1 24 Reaction of the Diene 1 with 2,2-Di(4-hydroxyphenyl)-hexafluoropropane 23.-A solution of 2,2-di(4-hydroxyphen- y1)hexafluoropropane 21 (1.39 g, 4.1 mmol) in acetonitrile (10 cm3) was added dropwise to a stirred mixture of the diene 1 (3.00 g, 8.3 mmol), caesium carbonate (5.40 g, 16.6 mmol) and acetonitrile (30 cm3).After 12 d at room temperature, the solid was filtered off, extracted with acetone and the extract dried (MgSO,). Evaporation of the extract under reduced pressure gave a residue which was sublimed in vacuo (80 "C, 0.10 mmHg) to give a white solid, which crystallised from acetone as white needles, and was subsequently identified as bis(trifruoromethy1)- methylenedi-p-phenylenedioxy-2,2'-bis[3,4-bis(tr@uoromethyl)-per-uorohexa-2,4-diene] 25 (3.5 g, 83%) (Found: C, 36.8; H, 0.7. C,,H,F,,O, requires C, 36.5; H, 0.8%); v,,,/cm-' 1710w (C==€),1670w (Ar), 1607m (Ar), 1515m (Ar), 1360m (CF) and 1330-1090s (CF); 6,[400 MHz; (CD,),CO] 7.31 (4 H, AB, J 8.8,2'-ArH) and 7.62 (4 H, AB, J 8.8, 3'-ArH); 6,[376 MHz; (CD,),CO] -61.14 (12 F, s, 1- and 3a-CF3), -62.62 (6 F, s, 4a-CF3), -64.63 (6 F, s, 7-CF,), -69.53 (6 F, s, 6-CF3) and -104.53 (2 F, m, 5-CF); m/z 1020 (M', 92%) and 951 (M+ k 69).6% I4a 1 25 Reaction of the Diene 27 with Sodium A4ethoxide.-A solution of sodium methoxide (0.20 g, 3.7 mmol) in methanol (5 cm3) was added to the diene 25 (0.20 g, 0.2 mmol) and methanol (10 cm3) and the mixture stirred at room temperature for 48 h. Removal of the solvent gave a residual solid which was extracted with diethyl ether and the extract dried (MgSO,). Subsequent solvent removal from the extract and recrystal- lisation of the residue from acetone, gave an off-white solid which was identified as bis(trzJEuoromethy1)methylenedi-J.CHEM. SOC. PERKIN TRANS. 1 1994 p-phenylenedioxy-2,2'-bis[5-methoxy-3,4-bis(trzjhoromethy1)-perfluorohexa-2,4-diene] 26 (0.15 g, 7373, m.p. 116 "C (Found: C, 38.1; H, 1.4. C,,H,,F,,O, requires C, 37.9; H, 1.3%); vmaX/cm-'2975w (CH), 17OOw (CS), 1655w (Ar), 1610w (Ar), 1513m (Ar), 1350m (CF) and 1325-1065s (CF); 6,(376 MHz; CDCl,) 3.99 (3 H, s, 5-CH,), 7.01 (2 H, JAB 8.4, 2'-ArH) and 7.39 (1 H, JAB 8.4, 3'-ArH); 6,(376 MHz; CDCl,) -60.20 (1 F, s, 3a-CF3), -60.96 (1 F, s, 1-or 4-CF,), -61.95 (1 F, s, 1-or 4a-CF3), -63.58 (1 F, s, 6-CF3) and -64.02 (1 F, s, 7-CF3); m/z 1044 (M', 34%). 63a CF3 CF3 CF3 CF374a 1 26 Acknowledgements We thank the following for financial support: The Daikin Co., Japan (to T.N.), the Science and Engineering Research Council and E. A. Technology for CASE support (to M. W. B., S. J. M., and J. F. S. V.). References 1 Part 38, M. W. Briscoe, R. D. Chambers, S. J. Mullins, T. Nakamura, J. F. S. Vaughan and F. G. Drakesmith, preceding paper. 2 R. D. Chambers and R. H. Mobbs in Advances in Fluorine Chemistry, eds. J. C. Tatlow and A. G. Sharpe, Butterworths, London, 1965, vol. 4, p. 50. 3 (a) I. L. Knunyants, L. S. German and B. L. Dyatkin, Zzv. Akad. Nauk SSSR Odtel. Khim. Nauk, 1956, 1353; (b) R. J. Koshar, T. C. Simmons and F. W. Hoffman, J. Am. Chem. Soc., 1957, 79, 1741; (c) T. J. Brice, J. D. Lazerte, L. J. Hals and W. H. Pearlson, J. Am. Chem. SOC.,1953,752698. 4 (a)V. A. Petrov, G. G. Belen'kii and L. S. German, Zzv. Akad. Nauk SSSR, Ser. Khim., 1981, 1920; (b) M. R. Bryce, R. D. Chambers, A. A. Lindley and H. C. Fielding, J. Chem. Soc., Perkin Trans. I, 1983,245 1. 5 (a)R. D. Chambers, A. A. Lindley and P. D. Philpot, J. Chem. Soc., Perkin Trans. I, 1979, 214; (b) C. J. Boriack, E. D. Laganis and D. M. Lemal, Tetrahedron Lett., 1978, 1015; (c) Y. Kobayashi, Y. Hanzawa, Y. Nakanish and T. Kashiwag, Tetrahedron Lett., 1978, 1019. 6 (a)J. Crookes, P. Roy and D. L. H. Williams, J. Chem. Soc., Perkin Trans. 2, 1989, 1015; (b) M. Bassett, G. Cerichell and B. Flows, Tetrahedron, 1988,44, 2997. 7 C. G. Krespan, J. Am. Chem. Soc., 1961,83,3434. Paper 4/03820G Received 23rd June 1994 Accepted 25th July 1994