Chapter 8 6
Functionalization of Pentafluoro-λ -sulfanyl (SF ) Olefins a n d Acetylenes Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on September 10, 2015 | http://pubs.acs.org Publication Date: April 29, 1994 | doi: 10.1021/bk-1994-0555.ch008
5
Rolf Winter and Gary L. Gard Portland State University, Portland, OR 97207-0751 In this review, the synthesis of SF -olefins and acetylenes and their conversion to compounds with new functional groups are described. It will be seen that there are only few reactions that allow the introduction of an SF -group, and that there are also only few reactions which lead to derivatives of unsaturated compounds. The chemical transformations of these simple unsaturated compounds into a number of useful and exciting products will be described. 5
5
The outstanding chemical stability of sulfur hexafluoride is to some degree carried over to its organic derivatives. Various methods are at hand to effect such a derivatization, e.g., treatment of disulfides, mercaptans or sulfides with fluorine (7), electrochemical fluorination (2), oxidation of aromatic disulfides with silver(II)fluoride (5). SF X (X = Cl,Br,SF ) adds across multiple bonds and forms adducts. Furthermore, tetrafluorosulfur ylides (F S=CR R ) add HF to form SF -compounds; however, as most of these ylides are formed from SF compounds, this method is only of limited value (4). The simple organic derivatives can undergo further reactions; in particular, the primary addition products of SF X and alkenes or alkynes can be dehydrohalogenated to yield alkenes or alkynes. Over 70 different compounds that contain both the SF -substituent and a double or triple bond were synthesized in the last thirty years and are listed in Table I. The high thermal, radiative and chemical stability of the pentafluorothio group make these compounds attractive as replacements for compounds that contain a trifluoromethyl group. The electronegativity value of the SF -group appears to be very high; by examining the C n.m.r. chemical shifts of a number of fluorosultones, a Pauling electronegativity of 3.62 is found (5). It is, however, comparatively more difficult to introduce this group into a molecule than a CF 5
5
4
1
2
5
5
5
5
5
13
3
Note: A common name for the SF group is pentafluorothio and will be used throughout the text. 5
0097-6156/94/0555-0128$08.00/0 © 1994 American Chemical Society In Inorganic Fluorine Chemistry; Thrasher, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1994.
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8.
6
Pentafluoro-\ -sulfanyl Olefins and Acetylenes
WINTER AND GARD
129
Table I. SF Alkenes Derivatives 5
Compound (Two-Carbon Alkenes)
IR(C=C) (CM* ) 1
BD
CO
Reference
...
41
(27)
SF CH=CHF
...
...
(29)
3.
SF CH=CHC1
1615
65-67
(20)
4.
SF C(C1)=CH
1616
64
(40)
5.
SF CH=CF
1748
28.1
(32,72)
6.
cis/trans SF CF=CHF
...
...
(17)
7.
SF CH=CFC1
8.
SF CF=CF
1.
SF CH=CH
2.
5
2
5
5
5
5
2
2
5
(48)
5
5
2
(27,31,72)
1786
19
(40)
9.
SF C(C1)=CF
2
1721
...
10.
SF CH=CHBr
1611
86±2
(20b)
11.
SF C(Br)=CH
...
86
(20)
12.
£/Z-SF CH=CFP(0)(OH)
1649
66(mp)
(61)
13.
cis/trans SF C(Br)=CHCl
50/52mm
(20)
14.
£-SF CF=CFP(0)(OH)
5
5
5
2
5
2
5
101(mp)
(61)
55 ±1/48mm
(20b)
1672
48
(43)
SF C(Br)=CH(SF )
1610
...
(22)
(SF ) C=CF
1706
88
(33,34)
5
2
...
15.
cis/trans SF C(Br)=CH(Br) 1573
16.
SF CF=CFI
17. 18.
5
5
5
5
5
2
2
Continued on next page
In Inorganic Fluorine Chemistry; Thrasher, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1994.
130
I N O R G A N I C F L U O R I N E C H E M I S T R Y : T O W A R D T H E 21ST C E N T U R Y
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Table I. Continued
Compound
IR(C=C)
(Three-Carbon Alkenes) 1.
SF5CH2CH=CH2
2.
1
(CM" )
Reference
BD(°C)
80-82
(27)
cis/trans SF CH=CHCH 1663
80-82
(27)
3.
rô-SF CH=CHOCH
1672
50/20mm
(20)
4.
ira>w-SF CH=CHOCH
1639
115
(20)
5.
SF CH=C(C1)CH
1653
92
(27)
1640
59/158mbar
(42)
1643
109±2
(23)
—
5
3
5
3
5
3
5
3
6.
SF CH C(C1)=CH
7.
SF CH=C(CH )Br
8.
SF C(CF )=CF
9.
SF CF C(C1)=CF
10.
£/Z-SF CH=C(CF )Br
5
2
5
2
3
5
3
5
2
5
2
2.
SF CH=C(CH ) 5
3
(32,49) (41)
1630/1637
93 ± 1
(22,23)
IR (C=C) 2
SF CH CHFCH=CH 5
47 ...
3
Compound (Four-Carbons) 1.
1722 ...
2
2
2
Bp(°C)
Reference
1668
102-106
(33)
...
...
a
...
...
(27) (20)
3.
SF CH CH(C1)CH=CH
4.
SF CH=CHCH=CHC1
...
—
5.
SF C(CH )=C(Cl)OCH
...
40-45/20mbar (24)
6.
SF CH=C(Br)OCH
1620 sh. at 15901
—
(26b)
7.
SF CF=CFCH CH I
...
...
(29)
8.
(SF CF=CF )
—
...
(52)
a
See M. Tremblay (8) reference in the cited literature.
5
2
5
5
3
5
5
2
5
2
2
2
3
2
In Inorganic Fluorine Chemistry; Thrasher, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1994.
8. WINTER AND GARD
6
Pentafluoro-\ -sulfanyl Olefins and Acetylenes
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Table I. Continued
Compound (Five or More Carbons)
IR (C=C)
Bp(°C)
1.
SF C(CH )=C(Cl)OC H
—
45/20mbar
(24)
2.
£/Z-SF CH=CFP(0)(OEt)
1655/1630
—
(61)
3.
SF CF=CFP(0)(OEt)
1666
3870.04mm
(60)
4.
[SF CF=CFPMe ] BF -
1660
159°(mp)
(43)
5.
£/Z-SF CH=CFP(0)(OSiMe )
1660/1640
—
(61)
6.
SF (CF ) CH OC(0)CH=CH
—
...
a
7.
SF CF=CFP(0)(OSiMe )
1665
7270.1mm
(60)
a
See J.C. Hansen and P.M. Savu (7) reference in the cited literature.
5
3
2
5
5
5
5
+
3
2
2
4
5
5
2
3
4
2
5
3
2
2
2
Reference
SF Cyclic, Heterocyclic, Aromatic Derivatives g
Compound (Mono SF )
IR(C=C) (cm' ) 1
5
F,S
Reference
Bp(°C)
72.0/48mm ( X = H ) (3,20) a
O
HC-CSF
o 5
II II
HC
161°
(27)
62°C/15mm
(33)
68-69°(mp) (R=H)
(20)
SF>
SF C-CH 5
• "
Ν
-
(R=C(0)N(CH ) ) 3
2
V
R
SF C = C-H 5
/ CH?
\
CR
\
1686(C=C) 48-50/10mm (R=H) 1652(CH=C-S)
(20)
CHo
/
= CR
1661
6574mm (R=CH ) 3
Continued on next page
In Inorganic Fluorine Chemistry; Thrasher, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1994.
131
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132
INORGANIC FLUORINE CHEMISTRY: TOWARD THE 21ST CENTURY
Table I. Continued
SF Cyclic, Heterocyclic, Aromatic Dervatives, cont'd. S
HC-CSFc
197-198°(mp)(R=H) (21) 78-78.5 (mp)(R=CH C(0)) 200-201 (mp) (R=C H NHC(0)) 116-117 (mp)(R=NH ) 3
CFLC Ν
V
6
5
2
SF,
7.
120°
CH =CH?
8.
SF C = CCF 5
3
\ / NiX,
a
1890/1865
-
(X=CO)
(26)
1750
137°C(mp) (X=P(C H ) ) 6
5
3
Numerous derivatives with X = m-N0 , /?-N0 , m-NH , p-NH2, m-OH, p-OH, m-C0 H, p-C0 H, m-CH=CH , etc. 2
2
2
2
2
2
See Reference Banks et al (7) in the cited literature.
In Inorganic Fluorine Chemistry; Thrasher, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1994.
6
Pentafluoro- X -sulfanyl Olefins and Acetylenes
WINTER AND GARD
Table I. Continued Compound (poly SF )
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S
Compound fpolv SF )
IR(C=C) Reference
?
SF, 1.
(73)
SR
γ-c
H
88/1.6mm ( X - N O J (3) (X=NH ) 80.7-81.5°(mp) (X=NH · HC1)
2.
2
X
2
SF, 3.
(7*)
SF. CH. ^
c - A CTL
ο = c-o 4.
N
163-164°(mp)
S F
SF (0>- = N-(0) 5
(3)
5
CH SF 2
5
(35) F SCH 5
2
Ο
4l
F S^^SF 5
7.
126-127°(mp)
(25)
5
SF^ 6°
(25)
SF« F,S
Continued on next page
In Inorganic Fluorine Chemistry; Thrasher, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1994.
134
INORGANIC FLUORINE CHEMISTRY: TOWARD THE 21ST CENTURY
Table I. Continued
SF Alkvne Derivatives Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on September 10, 2015 | http://pubs.acs.org Publication Date: April 29, 1994 | doi: 10.1021/bk-1994-0555.ch008
g
Compound
IR(C=C) fern' )
BpfQ
1
Reference
1.
SF C=CH
2118
6°C
(20,21)
2.
SF OCLi
...
...
(25)
3.
SF C=CCH
2661
65-70°C
(27)
4.
SF OC-OCH
2260
57.6°
(26)
5.
SF OC-Cl
...
-69°
(25)
6.
SF OC-CF
2295
14.4°
(22)
7.
SF OC-Br
...
-65°
(25)
8.
(CH ) SiOCSF
-8.5°C (mp) 96.9°
(25)
9.
SF CH=C(Br)OCH
...
(26)
10.
SF OC-Ag
2062
...
(20)
11.
SF OC-I
...
-52°(mp)
(25)
12.
SF OCSF
2220
51°
(22)
13.
IMg(OCSF )
...
...
(25)
14.
SF OC-OCSF
2180
5
5
5
3
5
5
5
3
5
3
3
5
2120 ( O C )
5
1620, sh. at 1590 (C=C) 5
5
5
5
5
5
5
15.
Co (CO) (HC=C-SF )
...
16.
Hg(OCSF )
...
17.
Co (CO) ((CH ) SiOC-SF )
2
6
5
5
2
2
6
3
3
5
18.
Co (CO) (HC=C-SF )
19.
Co (CO) (SF OCSF )
2
5
2
5
6
5
5
20.
Co (CO) (HOC-SF )
21.
C H HgOCSF
2
6
4
5
2
...
5
5
3
...
105°
(26b)
47°(mp)
(25)
—
(25)
135°(mp)
(25)
74°(mp)
(25)
149°(mp)
(25)
108°(mp)
(25)
100°(mp)
(25)
In Inorganic Fluorine Chemistry; Thrasher, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1994.
8.
6
Pentafluoro-\ -sulfanyl Olefins and Acetylenes
WINTER AND GARD
135
group, or generally, C F -group, and also rather more expensive. It is envisioned that SF -compounds could be useful dielectrics, replacements for fluorochlorohydrocarbons, very resistant polymers, fuel cell electrolytes with advantageous properties, blood substitutes, surfactants, high energy materials (explosives and rocket fuels (6)) or pesticides. In several cases, these expectations are seen to be fulfilled (7). In order to allow for ready access to these compounds, it was necessary to devise acceptably simple syntheses of both SF C1 and SF Br, which form an SF -C bond by addition across double and triple bonds. The use of S F has been described, either alone (8) or as a mixture with iodine (9); product mixtures were obtained with olefins and only selected olefins yielded any SF -compounds at all. n
2n+1
5
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5
5
5
2
10
5
The Synthesis of Pentafluorothio Halides (SF X) 5
Pentafluorothio chloride can be obtained by several different methods, the oldest one being first heating SF with cesium fluoride (at ca 150°C), potassium fluoride (300°C) or silver fluoride (300°C) and then treating the intermediate MSF with chlorine (M = Cs ca. 75% yield, Κ = 5-10 %, Ag =22 %) (10). The less expensive K F can be used instead at lower temperature (200-225°C) in a more cumbersome process and yields are also apparently very good (ca 80%) (77). The easiest method consists of allowing a frozen equimolar mixture of SF and C1F in the presence of a small amount of CsF to attain room temperature slowly (72). Care has to be taken that the C1F is completely free of C1F (C1F is prepared by heating C1F and Cl ). This can be achieved through low temperature distillation at -140°C; otherwise, dangerous explosive reactions can occur. The yield is almost quantitative. The compound SF Br was first obtained by heating a mixture of Br , BrF and SF (10% yield) (75), then by heating Br and S F (