R.W. Winter, G.L. Gard / Journal of Fluorine Chemistry 125 (2004) 549–552
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SF5Br is carried out in a similar fashion, the cis-product was
obtained in 100% yield. The trans- and cis-adducts were not
further characterized but used to prepare 2 and 3.
(temperature of sand bath); after 15 h, the volatile materials
were removed under vacuum by heating the reaction mixture
to 100 8C for 7 h and collecting the volatile materials in a
À78 8C trap (trap was attached to top of Vigerux columns).
To the condensate (2.5 g) a 20% NaOH solution was added
dropwise until the pH was 10–11; the lower layer was
removed, dried over Na2SO4, giving 0.81 g (3.97 mmol,
yield of 39%) of pure SF5C6H5 (3) as shown by GC–MS.
GC–MS spectrum: 204 (M)þ, 185 (M À F)þ, 127 (SF5)þ,
108 (SF4)þ, 96 (SC5H4)þ, 89 (SF3)þ, 77 (C6H3)þ, 70 (SF2)þ,
51 (SF)þ.
3.1.2. Preparation of trans/cis-1,4-diacetoxy-2-SF5-2-
cyclohexene (2)
In a 500-ml round-bottomed vessel equipped with a Teflon
stirring bar, 5.94 g (14.7 mmol) of trans-(1) (from reaction
above), 75 ml of acetone and 7.5 g of finely ground K2CO3
were refluxed for 28 h. The solids were removed by suction
filtration; evaporation of the filtrate gave the trans-product,
trans-(2), 4.65 g (14.4 mmol, yield of 98%) as an off-white
crystalline solid which when recrystallized from ethanol or
isopropanol gave large colorless crystals, mp 109–110 8C.
When the cis-compound (1) was reacted in a similar fashion,
the product cis-1,4-diacetoxy-2-SF5-2-cyclohexene, cis-(2)
was produced in 70% yield; mp 139–140 8C.
IR spectrum (neat, KBr, cmÀ1): 3079 (w), 2361 (w), 2337
(w), 1487 (m), 1454 (m), 1098 (m), 831 (s, sh 871), 756 (ms),
688 (m), 646 (m), 596 (m), 580 (m).
1H NMR (500 MHz, CDCl3, (CH3)4Si): d2,6 7.75
(d, J ¼ 7:95 Hz), d3,5 7.45 (t, J ¼ 7:33 Hz), d4 7.50
(t, J ¼ 7:33 Hz).
19F NMR (CDCl3, CCl3F): FA 84.0 (nine line pattern, 1F),
FB 61.9 (d-m, 4F), J ¼ 149:3 Hz.
3.1.2.1. Trans-derivative. IR spectrum (neat, KBr, cmÀ1):
3016 (vw), 2968 (w), 2948 (w), 2862 (vw), 1740 (vs), 1690
(w), 1657 (w), 1436 (w), 1375 (m), 1365 (m), 1304 (w), 1241
(s), 1222 (vs), 1199 (m-s), 1122 (w), 1094 (w), 1051 (w),
1015 (s, sh 1029), 987 (s, sh 974), 923 (w-m), 822 (vs,b), 737
(m), 672 (w), 647 (w-m), 593 (m), 558 (w-m), 492 (w), 468
(w-m).
1H NMR (500 MHz, CDCl3): d 5.86 (t, J ¼ 3:1 Hz, 1H), d
6.90 (d, J ¼ 4:68 Hz, 1H), d 5.51 (s, 1H), d 1.8–2.1
Hð5Þ þ Hð6Þ (m, overlap with CH3CO, 2s at 2.08, 2.09,
comb. 10H).
3.1.4. Preparation of trans-1,4-dihydroxy-2-SF5-
cyclohexene (4)
3.1.4.1. Hydrolysis method. Into a 100-ml round-bottomed
flask equipped with a Teflon stirring bar, 2.16 g (6.67 mmol)
of trans-(2), 10 ml of ethanol, 50 ml of water and 1.0 g of
p-toluenesulfonic acid monohydrate were added; the mixture
was refluxed for 20 h. The reaction was cooled to RT and
extracted six times with 15 ml of t-butylmethyl ether.
Evaporation of the extract left behind 1.58 g (6.58 mmol)
of an oil (99% yield) that slowly solidified; the product 4 was
shown to be pure by GC–MS and was recrystallized from a
mixture of methylene chloride and t-butylmethylether. The
mp was 129–130 8C.
19F NMR (CDCl3, CCl3F): FA 82.3 (nine line pattern, 1F),
FB 57.5 (d-m, 4F, J ¼ 149:0 Hz).
3.1.2.2. Cis-derivative. IR spectrum (neat, KBr, cmÀ1):
3074 (vw), 2969 (w), 2928 (w), 2880 (w), 1738 (vs),
1693 (w), 1676 (w), 1656 (w), 1449 (w), 1430 (w), 1371
(m), 1304 (w), 1233 (vs, sh 1246), 1205 (m-s), 1147 (w),
1093 (w), 1049 (m), 1020 (m), 993 (m), 959 (m), 920 (w),
861 (s), 851 (vs), 833 (vs), 821 (vs), 745 (s), 669 (w), 647
(m), 615 (w), 598 (m), 572 (w-m), 537 (w-m), 514 (w),
483 (w).
3.1.4.2. Transesterfication method. In a 500-ml round-
bottomed flask, 21.00 g (64.8 mmol) of trans-(2), 250 ml
of CH3OH and CH3ONa (50 mg of Na in 3 ml of CH3OH,
2.17 mmol) were mixed together. After ꢀ18 h, a GC–MS
spectrum showed complete conversion to the trans-diol.
Several drops of 6N HCl were added until the solution was
slightly acidic. The volatile components were removed under
vacuumleaving behind 15.84 g of product (includes NaCl and
traces of water). The trans-diol (4) can be recrystallized as
shown above.
IR spectrum (neat, KBr, cmÀ1): 3225 (b, m), 2966 (w),
2938 (w), 2855 (w), 2707 (w), 1441 (w), 1415 (w), 1354 (w),
1305 (w), 1278 (w), 1260 (w), 1196 (w-m), 1090 (w-m),
1028 (m-s), 997 (s), 952 (w), 920 (w-m, sh 929), 831 (vs,
sh 848, 865), 803 (vs), 749 (m), 715 (w), 652 (w-m), 629
(w-m), 598 (w-m), 569 (w-m), 478 (w).
1H NMR (500 MHz, CDCl3): d 5.79 (t, br., 1H), d 6.72 (d,
J ¼ 2:8 Hz, 1H), d 5.53 (s, br., 1H), d 1.75–2.1 (m, overlap
with CH3CO, s at 2.2, 2.09, comb. 10H).
19F NMR (CDCl3, CCl3F): FA 82.5 (nine line pattern, 1F),
FB 58.0 (d-m, 4F), J ¼ 149:0 Hz.
High-resolution mass spectrum (HRMS): The trans-iso-
mer ðM À HÞþ ¼ 323:03883; Calc: ¼ 323:03765 and
ðMHÞþ ¼ 325:05447; Calc: ¼ 325:05330. The cis-isomer
ðM À HÞþ ¼323:03716; Calc:¼323:03765; and ðMHÞþ ¼
325:05246; Calc: ¼ 325:05330.
3.1.3. Preparation of SF5C6H5 (3) via thermolysis of 2
Into a 50-ml round-bottomed flask equipped with a Teflon
stirring bar and three stacked Vigerux columns (air conden-
ser), 3.29 g (10.2 mmol) of trans-(2), and 25 ml of dipheny-
lether were added. The mixture was heated to 265–270 8C
1H NMR (d6-acetone, (CH3)4Si): d1 4.60 (br. s, 1H), d4
4.40 (br. s, 1H), d3 6.60 (d, J ¼ 4:17 Hz, 1H), d5,6 2.0
(m, 4H, D2O), dOH 4.15 (s, 2H).
19F NMR (CDCl3, CCl3F): FA 85.5 (nine line pattern, 1F),
FB 58.7 (d-m, 4F), J ¼ 149:9 Hz.