JPH04264041A - Production of difluoromethylene compound - Google Patents

Abstract

PURPOSE:To efficiently and safely obtain the title compound at low cost in high selectivity under mild conditions by reaction of a dithioacetal with a dihydrogen quaterary ammonium trifluoride in the presence of a halonium ion generator. CONSTITUTION:The objective compound of formula III (e.g. 4-difluoromethyl-1- propylbenzene) can be obtained by reaction of (A) a dithioacetal of formula I (R<1> is aryl or vinyl; R<2> is H, aryl, vinyl or alkyl; R<3> and R<4> are each alkyl or aryl, or being combined together with S into a ring) [e.g. 2-(4- propylphenyl)-1,3-dithiorane] with (B) a dihydrogen quaternary ammonium trifluoride of formula II (R<a>-R<d> are each alkyl) (e.g. dihydrogen tetrabutylammonium trifluoride) in the presence of (C) a halonium ion generator (e.g. 1,3-dibromo-5,5-dimethylhydantoin). By the present method, the objective compound can be obtained in high functional selectivity and in high yield.

Description

Detailed Description of the Invention [0001] [Industrial Application Field] The present invention relates to the following general formula (III) [
[0002] [0003] (In the formula, R1 represents a substituted or unsubstituted aryl group or a vinyl group, and R2 represents a hydrogen atom, a substituted or unsubstituted aryl group, a vinyl group, or a straight-chain or branched alkyl group. The present invention relates to a method for producing a difluoromethylene compound represented by (representing a group). The difluoromethylene compound represented by the general formula (III) is expected to be used as a raw material for the synthesis of pharmaceuticals and agricultural chemicals containing a difluoromethylene group (for example, Bi
oorganic Chem. , 18, 53
0 (1990)). [0005] As a method for synthesizing the difluoromethylene compound represented by the above general formula (III), (1) a ketone or aldehyde is synthesized with sulfur tetrafluoride and hydrogen fluoride (for example, Org. React., 21, 20
(1974)) or diethylaminosulfur trifluoride (DAST) (e.g. J. Org. Chem
．． , 40, 574 (1975)); (2) a method of treating dithioacetal with a combination of a halonium ion generator such as N-haloamide and anhydrous hydrogen fluoride-pyridine complex (for example, J.
Org. Chem. , 51, 3508
(1986)). Sulfur tetrafluoride and hydrogen fluoride used in method (1) are highly toxic low-boiling compounds (the boiling point of sulfur tetrafluoride is -40°C and the boiling point of hydrogen fluoride is 19.5°C). Difficult to handle. Furthermore, it is often necessary to carry out the reaction at high temperatures in an autoclave made of a special material (eg Hastelloy C, etc.). Furthermore, sulfur tetrafluoride is highly reactive and cannot be used to difluoromethyleneate substrates with functional groups, such as alcohols. D.A.
Methods using ST also often require high temperatures and long periods of time. In addition, hydroxyl groups also undergo fluorination, so they must be protected. In method (2), the reaction system becomes strongly acidic, so if it is used with a substrate that has acid-sensitive functional groups such as epoxides, a difluoromethylene compound will not be obtained, but only a complex reaction mixture will be obtained. Yes (see Reference Example 1). Problems to be Solved by the Invention In synthesizing the difluoromethylene compound, the present inventors found that (1) it is inexpensive;
(2) It is safe, (3) glass containers can be used, (4) it can be applied to substrates that are unstable under acidic conditions, and (
5) As a result of intensive studies on reaction conditions that allow for fluorination under mild conditions, it was found that reacting dithioacetal with quaternary ammonium dihydrogen trifluoride and a halonium ion generator would produce the desired difluoromethylene compound efficiently and at high levels. We have discovered that it can be produced selectively. [Means for Solving the Problems] The present invention provides general formula (I)
##STR5## In the formula, Ra, Rb, Rc and Rd each independently represent a substituted or unsubstituted alkyl group. Together with the generator, the general formula (II) [0012] (wherein R1 represents a substituted or unsubstituted aryl group or a vinyl group, and R2 represents a hydrogen atom, a substituted or unsubstituted aryl group, a vinyl R3 and R4 each independently represent a substituted or unsubstituted straight-chain or branched alkyl group or aryl group. R3 and R4 represent a sulfur atom and a straight-chain or branched alkyl group. can be combined to form a ring) to form a dithioacetal of the general formula (III).
[0013] This invention relates to a method for producing a difluoromethylene compound represented by the following formula (wherein R1 and R2 are the same as above). Examples of the quaternary ammonium dihydrogen trifluoride represented by the general formula (I) include tetramethylammonium dihydrogen trifluoride, tetraethylammonium dihydrogen trifluoride, and tetrabutylammonium dihydrogen trifluoride ( (nBu4N+)(H2F3-)), benzyltrimethylammonium dihydrogen trifluoride, benzyltriethylammonium dihydrogen trifluoride, and cetyltrimethylammonium dihydrogen trifluoride. These can be easily synthesized from 50% hydrofluoric acid, potassium fluoride and quaternary ammonium fluoride (Bull. Soc.
Chim. Fr. , 910 (1986
)). The amount of quaternary ammonium dihydrogen trifluoride to be used in the present invention ranges from 1 equivalent to a large excess, but 1 to 4 equivalents is preferred in consideration of economic efficiency. As the halonium ion generator, N-bromosuccinimide (NBS), 1,3-dibromo-5
, 5-dimethylhydantoin (DBH), N-bromoacetamide (NBA), 2,4,4,6-tetrabromo-2,5-cyclohexadienone, N-iodosuccinimide (NIS), etc. . The amount of the halonium ion generator used in the present invention ranges from 1 equivalent to a large excess amount, and from 1 to 3 equivalents is preferred in consideration of economic efficiency. In the dithioacetal represented by the general formula (II), the aryl group for R1 or R2 is a substituted or unsubstituted phenyl group, 1-naphthyl group, 2-
Naphthyl group, 1-anthracenyl group, 2-anthracenyl group, 9-anthracenyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-thiophenyl group, 3-
Examples include a thiophenyl group and a 2-pyrimidino group. The substituent on the aromatic ring is preferably a substituent other than an electron-withdrawing substituent, such as a straight chain or branched alkyl group having 1 to 20 carbon atoms, a phenyl group, a biphenyl group, a 1-naphthyl group, a 2- Naphthyl group, 1-anthracenyl group, 2-anthracenyl group, 9-anthracenyl group,
2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2
- Aryl groups such as thiophenyl group, 3-thiophenyl group, 2-pyrimidino group, alkenyl group such as vinyl group, propenyl group, butenyl group, methoxy group, ethoxy group, butoxy group, heptyloxy group, octyloxy group Alkoxyl group such as acetoxyl group, acyloxyl group such as butoxyl group, alkoxymethyloxyl group such as methoxymethyloxy group, methoxyethoxymethyloxy group, aryloxyl group such as phenyloxyl group, naphthoxyl group, 2 -Oxa-3-
Examples include groups having a sugar skeleton such as hydroxymethyl-4,5,6-trihydroxy-cyclohexyloxy group, and further alkyl groups, aryl groups, etc. on these substituents on the aromatic ring. It may be substituted with a group having a cyclic ether structure or a sugar skeleton such as a group, an alkenyl group, a nitro group, a cyano group, an alkoxycarbonyl group, an alkoxyl group, a hydroxyl group, a halogen, a sulfonyl group, or an epoxide. Substituents on the vinyl group of R1 or R2 include a straight chain or branched alkyl group having 1 to 20 carbon atoms, a phenyl group, a biphenyl group, a 1-naphthyl group,
2-naphthyl group, 1-anthracenyl group, 2-anthracenyl group, 9-anthracenyl group, 2-pyridyl group, 3
-pyridyl group, 4-pyridyl group, 2-thiophenyl group,
Aryl groups such as 3-thiophenyl group, 2-pyrimidino group, alkenyl group such as vinyl group, propenyl group, butenyl group, alkoxyl group such as methoxy group, ethoxy group, butoxy group, heptyloxy group, octyloxy group 2-oxa-3 -Hydroxymethyl-
Examples include groups having a sugar skeleton such as a 4,5,6-trihydroxy-cyclohexyloxy group, and on these substituents for the vinyl group, alkyl groups, aryl groups, alkenyl group, nitro group,
Cyano group, alkoxycarbonyl group, alkoxyl group,
It may be substituted with a hydroxyl group, a halogen, a sulfonyl group, a group having a cyclic ether structure or a sugar skeleton such as epoxide. The alkyl group of R2 has 1 to 2 carbon atoms.
Up to 0 straight-chain or branched alkyl groups can be used. On this alkyl group, phenyl group, biphenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthracenyl group, 2-anthracenyl group, 9-anthracenyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group base,
Aryl groups such as 2-thiophenyl group, 3-thiophenyl group, 2-pyrimidino group, alkenyl group such as vinyl group, propenyl group, butenyl group, methoxy group, ethoxy group, butoxy group, heptyloxy group, octyloxy group alkoxyl groups such as acetoxyl groups, acyloxyl groups such as butoxyl groups, alkoxymethyloxyl groups such as methoxymethyloxy groups, methoxyethoxymethyloxy groups, aryloxyl groups such as phenyloxyl groups, naphthoxyl groups, 2-oxa-3
-Groups with sugar skeletons such as hydroxymethyl-4,5,6-trihydroxy-cyclohexyloxy groups, nitro groups, cyano groups, hydroxyl groups, alkoxycarbonyl groups, halogens, sulfonyl groups, and cyclic ethers such as epoxides. A group having a ter structure can be substituted. Furthermore, on these substituents for alkyl groups, there are further substituents such as alkyl groups, aryl groups, alkenyl groups, nitro groups, cyano groups, alkoxycarbonyl groups, alkoxyl groups, hydroxyl groups, halogens, sulfonyl groups, and epoxides. A group having a cyclic ether structure or a sugar skeleton may be substituted. R3 and R4 each independently represent a substituted or unsubstituted linear or branched alkyl group or aryl group. Examples of the alkyl group, aryl group, and substituents thereof are the same as those exemplified for R1 and R2. Further, R3 and R4 may form a ring together with the sulfur atom to which they are bonded, and a 1,3-dithiolane or 1,3-dithiane skeleton can be exemplified. This substrate, dithioacetal, can be easily obtained by treating an aldehyde or ketone with a thiol. It can also be easily obtained by treating a dithioacetal in which R2 is a hydrogen atom with a base and then with an electrophile (alkyl halide, carbonyl compound, epoxide, etc.). A solvent may be used during the reaction. Any solvent can be used as long as it does not participate in the reaction.
Hexane, benzene, toluene, acetonitrile, diethyl ether, tetrahydrofuran, 1,2-dimethoxyethane, dichloromethane, 1,2-dichloroethane,
Examples include carbon tetrachloride. Further, these may be used as a mixture as appropriate. [0023] The reaction depends on the substrate, but from -100°C to 1
It can be carried out in the temperature range of 00°C. However, in order to shorten the reaction time and increase selectivity, it is necessary to
It is preferable to carry out between According to this method, difluoromethyleneation of substrates to which conventional methods cannot be applied, such as substrates having hydroxyl groups or acid-sensitive functional groups, can be carried out without damaging these functional groups.
C(SR3)(SR4) structure is selectively converted to =CF2 structure, and there is an advantage that the target product can be obtained in good yield and with high functional group selectivity (see Example 18 and Reference Example 1).
. The present invention will be explained in detail below with reference to Examples and Reference Examples. [Example] Example 1. 4-difluoromethyl-1-
Synthesis of propylbenzene (IV) [Chemical 8] 2-(4-propylphenyl)-1,3-
Dithiolane (112 mg, 0.5 mmol
) and (nBu4N) + (H2F3) - (450 mg
, 1.5 mmol) of dichloromethane (1.5
DBH, (320 mg, 1.mL) solution.
1 mmol) was added at -78°C, the temperature was gradually raised to room temperature, and the mixture was further stirred at room temperature for 1 hour. The reaction mixture was poured into a mixed aqueous solution of sodium hydrogen carbonate and sodium hydrogen sulfite, and extracted with diethyl ether (10 mL
x3). After drying the organic layer over anhydrous sodium sulfate, it was filtered, the solvent was distilled off under reduced pressure, and the residue was purified by silica gel preparative TLC.
mg (0.37 mmol, 74%) was obtained. IR: (neat) 2990,
2955, 2900, 1920, 172
8, 1620, 1518, 1462,
1425, 1380, 1304, 1257
, 1224, 1183, 1122, 1
084, 100, 1028, 832,
800 cm-1.1H-NMR (CDCl3-
Me4Si): δ 7.45 (d, J
= 8 Hz, 2H), 7.25 (
d, J = 8 Hz, 2H), 6
．． 63 (t, J = 57 Hz,
1H), 2.64 (t, J = 7H
z, 2H), 1.66 (tq, J = 7
, 7 Hz, 2H), 0.96 (t
, J = 7 Hz, 3H). M.S.
m/z (relative intensity) 171 (M++1,
3), 170 (M+, 28). 003
0] Example 2. Synthesis of 4-difluoromethyl-1-propylbenzene (IV) ##STR9## The title compound was prepared using NIS instead of the above DBH.
2-(4-propylphenyl)-1,3-dithiolane (112 mg
, 0.5 mmol) to NIS (250 mg
, 1.1 mmol) and (nBu4N) + (H2F3
)-(450 mg, 1.5 mmol) to obtain 62 mg (0.36 mmol)
1, 72%) was obtained. Example 3. 4-difluoromethyl-1
-Synthesis of propylbenzene (IV) ##STR10## The title compound was prepared in the same manner as in Example 1, with 2-
(4-propylphenyl)-1,3-dithiane (119
mg, 0.5 mmol) to DBH (320
mg, 1.1 mmol) and (nBu4N)
+(H2F3)-(450 mg, 1.5 mmo
52 mg (0.31
mmol, 61%) was obtained. Example 4. 4-difluoromethyl-1
-Synthesis of propylbenzene (IV) ##STR11## The title compound was prepared in the same manner as in Example 1 except that NBS was used instead of DBH and the amount of dichloromethane used was 3 mL. , 2-(4-propylphenyl)-1,3-dithiane (238 mg,
1 mmol) with NBS (400 mg,
2.2 mmol) and (nBu4N) + (H2F3)
- (900 mg, 3 mmol) to produce 105 mg (0.62 mmol,
62%) was obtained. Example 5. Synthesis of butyl 4-difluoromethylphenyl ether (V) ##STR12## The title compound was prepared in the same manner as in Example 1, with 2-
(4-butoxyphenyl)-1,3-dithiolane (11
2 mg, 0.5 mmol) was added to DBH (32 mg, 0.5 mmol).
0 mg, 1.1 mmol) and (nBu4N)+
(H2F3)-(450 mg, 1.5 mmol
) by treatment with 90 mg (0.45
mmol, 90%) was obtained. IR: (neat) 2988,
2900, 1900, 1804, 172
8, 1618, 1594, 1520,
1471, 1431, 1383, 1310
, 1254, 1224, 1177, 1
120, 1071, 1021, 973,
835, 640 cm-1.1H-NMR
(CDCl3-Me4Si): δ 7.42
(d, J = 9 Hz, 2H),
6.95 (d, J = 9 Hz,
2H), 6.60 (t, J = 57
Hz, 1H), 4.00 (t, J
=7 Hz, 2H), 1.9-1.2 (
m, 4H), 0.96 (t, J =
7Hz, 3H). MS m/z (
Relative intensity) 201 (M++1, 4), 20
0 (M+, 31). Example 6.
Synthesis of butyl 4-difluoromethylphenyl ether (V) ##STR13## The title compound was synthesized using 2-(4-butoxy) in the same manner as in Example 1 except that NIS was used instead of DBH. phenyl)-1,3-dithiolane (112 mg,
0.5 mmol) to NIS (250 mg, 1
．． 1 mmol) and (nBu4N)+(H2F3)-
(450 mg, 1.5 mmol) to produce 86 mg (0.43 mmol,
86%) was obtained. Example 7. Synthesis of butyl 4-difluoromethylphenyl ether (V) ##STR14## The title compound was prepared in the same manner as in Example 1, with 2-
(4-butoxyphenyl)-1,3-dithiane (134
mg, 0.5 mmol) to DBH (320
mg, 1.1 mmol) and (nBu4N)+
(H2F3)-(450 mg, 1.5 mmo
81 mg (0.41
mmol, 81%) was obtained. Example 8. Synthesis of butyl 4-difluoromethylphenyl ether (V) [Chemical formula 15] The title compound was prepared as follows except that NBS was used instead of DBH and the amount of dichloromethane used was 3 mL. 2-(4-butoxyphenyl)-1,3-dithiane (252 mg,
0.94 mmol) in NBS (400 mg
, 2.2 mmol) and (nBu4N) + (H2
168 mg (0.84 mmol,
89%) was obtained. Example 9. Synthesis of 4-difluoromethylbiphenyl (VI) ##STR16## The title compound was synthesized from 2-difluoromethylbiphenyl (VI) in the same manner as in Example 1.
(4-phenylphenyl)-1,3-dithiolane (12
9 mg, 0.5 mmol) was added to DBH (32
0 mg, 1.1 mmol) and (nBu4N)+
(H2F3)-(450 mg, 1.5 mmol
) by treatment with 83 mg (0.41
mmol, 81%) was obtained. IR: (KBr) 3098,
3057, 3000, 1618, 1573,
1491, 1453, 1417, 138
1, 1319, 1228, 1080,
1024, 840, 768, 740,
694cm-1.1H-NMR (CDCl3-Me
4Si): δ 7.8-7.3 (m, 1
1H), 6.73 (t, J = 56
Hz, 1H). MS m/z (relative intensity) 205 (M++1, 14), 204
(M+, 100), 203 (M+-1,
30). Example 10. Synthesis of 4-difluoromethylbiphenyl (VI) [Chemical formula 17] The title compound was prepared in the same manner as in Example 1 except that NBS was used instead of DBH and the amount of dichloromethane used was 3 mL. and 2-(4-phenylphenyl)-1,3-dithiolane (258 mg
, 1 mmol) with NBS (400 mg,
2.2 mmol) and (nBu4N) + (H2F3
)-(900 mg, 3 mmol) to obtain 96 mg (0.47 mmol,
47%) was obtained. Example 11. Synthesis of 4-difluoromethylbiphenyl (VI) ##STR18## The title compound was synthesized from 2-difluoromethylbiphenyl (VI) in the same manner as in Example 1.
(4-phenylphenyl)-1,3-dithiane (136
mg, 0.5 mmol) to DBH (320
mg, 1.1 mmol) and (nBu4N)
+(H2F3)-(450 mg, 1.5mm
86 mg (0.42
mmol, 84%) was obtained. Example 12. Synthesis of 1-difluoromethylnaphthalene (VII) ##STR19## The title compound was synthesized from 2-difluoromethylnaphthalene (VII) in the same manner as in Example 1.
(1-naphthyl)-1,3-dithiolane (116 m
g, 0.5 mmol) to DBH (320 m
g, 1.1 mmol) and (nBu4N) + (H2F
3) - (450 mg, 1.5 mmol) to give 73 mg (0.41 mmol)
ol, 82%) was obtained. IR: (neat) 3178,
2980, 1730, 1692, 158
4, 1515, 1408, 1400,
1384, 1350, 1318, 1260
, 1244, 1220, 1176, 1
110, 1080, 1020, 885,
860, 804, 782 cm-1.1H
-NMR (CDCl3-Me4Si): δ
8.18 (d, J = 7 Hz,
1H), 8.1-7.8 (m, 3H),
7.8-7.5 (m, 3H), 7.13
(t, J = 55 Hz, 1H). M
S m/z (relative intensity) 179 (M++
1, 11), 178 (M+, 100)
, 177 (M+-1, 48). 00
66] Example 13. Synthesis of 1-difluoromethylnaphthalene (VII) ##STR20## The title compound was synthesized from 2-difluoromethylnaphthalene (VII) in the same manner as in Example 1.
(1-naphthyl)-1,3-dithiane (123 mg
, 0.5 mmol) and DBH (320 mg,
1.1 mmol) and (nBu4N) + (H2F3
) - (450 mg, 1.5 mmol) to obtain 75 mg (0.42 mmol)
1, 84%) was obtained. Example 14. 1,1-difluoro-
Synthesis of 1-(4-methoxyphenyl)propane (VIII) [0070] The title compound was synthesized from 2-ethyl-2- in the same manner as in Example 1 except that NIS was used instead of DBH. (
4-methoxyphenyl)-1,3-dithiane (254
mg, 1 mmol) to NIS (500 m
g, 2.2 mmol) and (nBu4N) + (H
2F3)-(900 mg, 3 mmol) to give 156 mg (0.84 mmol)
1, 84%) was obtained. IR: (neat) 2985,
2948, 2850, 1724, 161
5, 1582, 1519, 1463,
1438, 1412, 1381, 1360
, 1320, 1250, 1128, 1
110, 1096, 1029, 976,
940, 832 cm-1.1H-NMR
(CDCl3-Me4Si): 7.38 (d,
J = 9 Hz, 2H), 6.9
0 (d, J = 9 Hz, 2H)
, 3.80 (s, 3H), 2.15
(tq, J = 17, 7 Hz,
1H), 0.94 (t, J = 7H
z, 3H). MS m/z (relative intensity)
187 (M++1, 2), 186 (M
+, 21). Example 15. 1,1-
Difluoro-1-(4-methoxyphenyl)propane (
Synthesis of VIII) [Chemical Formula 22] The title compound was prepared in the same manner as in Example 1 except that NBS was used instead of DBH and the amount of dichloromethane used was 3 mL. -2
-(4-methoxyphenyl)-1,3-dithiane (25
4 mg, 1 mmol) in NBS (400 m
g, 2.2 mmol) and (nBu4N) + (H
2F3)-(900 mg, 3 mmol) to obtain 125 mg (0.67 m
mol, 67%) was obtained. Example 16. 1,1-difluoro-2
-Methyl-1-(4-methoxyphenyl)octane (I
Synthesis of -1,3-dithiane (85 mg, 0.25 mmol) in NIS
(125 mg, 0.55 mmol) and (n
Bu4N)+(H2F3)-(250 mg, 0
．． 63 mmol)
mg (0.23 mmol, 94%) was obtained. IR: (neat)
2950, 2880, 1732, 1620
, 1590, 1520, 1479, 1
420, 1383, 1312, 1254,
1180, 1107, 1040, 98
3,837 cm-1. 1H-NMR (C
DCl3-Me4Si): 7.38 (d,
J = 9 Hz, 2H), 6.92
(d, J = 9 Hz, 2H),
3.82 (s, 3H), 2.4-1.9
(m, 1H), 1.7-1.0(m,
8H), 0.98 (d, J = 7
Hz, 3H), 0.86(t, J =
5Hz, 3H). MS m/z (relative intensity) 271 (M++1, 2), 27
0 (M+, 12). Example 17.
Synthesis of difluorodiphenylmethane (X) ##STR24## The title compound was synthesized from 2,2-diphenyl-1,3-dithiolane (258 mg, 1 mmo
l) to NIS (500 mg, 2.2 mmo
l) and (nBu4N) + (H2F3) - (900 m
g, 3 mmol)
8 mg (0.92 mmol, 92%) was obtained. IR: (neat) 3053,
3030, 1722, 1492, 144
6, 1380, 1320, 1268,
1220, 1080, 1045, 1020
, 953, 910, 762, 692,
640 cm-1.1H-NMR (CDCl
3-Me4Si): δ 7.7-7.4 (m
, 10H). MS m/z (relative intensity)
205 (M++1, 10), 204
(M+, 73), 203 (M+-1,
25). Example 18. Synthesis of 1,1-difluoro-1-(4-methoxyphenyl)-3-butanol (XI) [Image Omitted] The title compound was the same as in Example 1 except that NIS was used instead of DBH. and 2-(2-hydroxypropyl)-2-(4-methoxyphenyl)-1,3
-dithiane (142 mg, 0.5 mmol
) to NIS (250 mg, 1.1 mmol
) and (nBu4N) + (H2F3) - (450 mg
, 1.5 mmol).
9 mg (0.41 mmol, 82%) was obtained. IR: (neat) 3400,
2952, 2910, 2830, 172
0, 1610, 1581, 1513,
1460, 1375, 1302, 1246
, 1173, 1100, 1021, 9
79, 938, 870, 829, 80
0, 758, 733, 603, 560cm
-1.1H-NMR (CDCl3-Me4Si):
δ 7.43 (d, J = 9Hz
, 2H), 6.94 (d, J =
9 Hz, 2H), 4.2-4.0 (
m, 1H), 3.82 (s, 3H),
2.5-2.0 (m, 2H), 1.8
8 (br s, 1H), 1.21 (
d, J=6 Hz, 3H). MS m/z
(Relative intensity) 217 (M++1, 4),
216 (M+, 28). Example 19
．． 1. Synthesis of 1-difluoro-1-(4-methoxyphenyl)-3,4-epoxybutane (XII) [Image Omitted] The title compound is the same as the example except that NIS is used instead of DBH. 1, 2-(2,3-epoxypropyl)-2-(4-methoxyphenyl)-1,
3-dithiane (141 mg, 0.5 mmo
l) to NIS (250 mg, 1.1 mmo
l) and (nBu4N) + (H2F3) - (450 m
g, 1.5 mmol), 66 mg (0.31 mmol, 62%) was obtained. IR: (neat) 3080,
3035, 2996, 2956, 287
0, 1732, 1620, 1592,
1521, 1469, 1420, 1388
, 1314, 1258, 1181, 1
117, 1083, 1028, 1001,
984, 948, 840, 808,7
70, 690, 610, 567 cm-
11H-NMR (CDCl3-Me4Si):
δ 7.45 (d, J = 9 Hz
, 2H), 6.96 (d, J= 9
Hz, 2H), 3.84 (s, 3
H), 3.2-3.0 (m, 1H),
2.76 (dd, J= 5, 5 Hz
, 1H), 2.7-2.1 (m, 3H
). MS m/z (relative intensity) 215 (
M++1, 3), 214 (M+, 27
). Reference example 1. 1.1-difluoro-1-
(4-methoxyphenyl)-3,4-epoxybutane (
Synthesis of XII) [Chemical Formula 27]
51, 3508 (1986)) to prepare 2-(2,3-epoxypropyl)-2-(
4-methoxyphenyl)-1,3-dithiane (70
mg, 0.25 mmol) to DBH (75 mg
, 0.26 mmol, 1.05 equivalent) and H
F-pyridine complex (70/30w%, 0.125
mL, 41 equivalents as fluoride ion) gave a very complex reaction mixture in which the title compound was not present. Example 20. 3,3-difluoro-1
-Synthesis of phenylpropene (XIII) [Chemical formula 28] The title compound was prepared in the same manner as in Example 1 except that NIS was used instead of DBH and the amount of dichloromethane used was 3 mL. , 2-(2-phenylethenyl)-1,3-dithiolane (208 mg
, 1 mmol) to NIS (200 mg,
2.2 mmol) and (nBu4N) + (H2F3
)-(900 mg, 3 mmol) to produce 82 mg (0.53 mmol,
53%) was obtained. IR: (neat) 3060,
3030, 2956, 2920, 172
5, 1670, 1659, 1578,
1492, 1446, 1382, 1134
, 1072, 1054, 1011, 9
62, 748, 691 cm-11H-NM
R (CDCl3-Me4Si): δ 7.5
(m, 5H), 7.1-6.8 (m,
1H), 6.5-6.2 (m, 1H),
6.32 (dt, J = 5, 54
Hz, 1H). MS m/z (relative intensity) 155 (M++1, 10), 154
(M+, 28), 153 (M+-1,
48).

Claims (1)

[Claims] Claim 1: Quaternary ammonium dihydrogen trifluoride represented by the general formula (I): (wherein Ra, Rb, Rc and Rd each independently represent a substituted or unsubstituted alkyl group) In the presence of a halonium ion generator,
General formula (II) [Formula 2] (wherein R1 represents a substituted or unsubstituted aryl group or vinyl group, and R2 represents a hydrogen atom, a substituted or unsubstituted aryl group, a vinyl group, or a straight-chain or branched alkyl group) R3 and R4 each independently represent a substituted or unsubstituted linear or branched alkyl group or aryl group.Also, R3 and R4 combine with the sulfur atom to form a ring. ) is reacted with a dithioacetal represented by the general formula (I
II) A method for producing a difluoromethylene compound represented by Formula 3 (wherein R1 and R2 are the same as above).