140
K. Ishihara et al. / Journal of Fluorine Chemistry 106 (2000) 139±141
and the oxygen atom in the tris(tr¯uoromethanesulfonyl)-
Furthermore, we have found that acetonitrile was quantita-
tively inserted into 2 to give 4 during the pyrolysis of 1. The
novel structure of 4 is fascinating as a ligand bearing a new
functional group for a metal ion.
methide anion [4]. In the case of PhN2 C(SO2F)3 , pyr-
olysis under the same conditions has given only
PhO(F)S(O)=C(SO2F)2 and no (FSO2)3CPh has been
detected [5].
3. Experimental
Melting points were measured on a Yanaco apparatus and
are uncorrected. All reactions were carried out in an ordinary
glass-ware. Bis(tri¯uoromethanesulfonyl)methane was pre-
pared from trimethylsilylmethyl lithium and tri¯uorometha-
nesulfonic anhydride according to the literature method [6].
All other reagents were commercially available and were
puri®ed before use as appropriate. IR spectra were obtained
on a FTIR-8100 Shimadzu spectrophotometer using thin
(3)
The solvent effect was investigated for the pyrolysis of 1
at 608C. Unfortunately, no 2 was detected in toluene, N,N-
dimethylformamide, or acetonitrile, and only a trace amount
of 2 was detected by 19F NMR spectrum in acetone, nitro-
methane, ethyl acetate, or THF.
1
®lms on NaCl plates or KBr ®lms. 19F NMR and H NMR
Very interestingly, the pyrolysis of 1 gave another novel
compound 4 quantitatively when heated in acetonitrile at
608C (Eq. (4)). In this reaction, bis(tri¯uoromethanesulfo-
nyl)methide anion reacted with an ammonium ion inter-
mediate which was generated by nucleophilic attack of the
nitrogen atom in acetonitrile to the phenyl cation formed. A
trace amount of acetanilide, which would be obtained by
hydrolysis of the same intermediate, was also detected.
Other nitriles such as isobutyronitrile also reacted with 1
to afford compounds analogous to 4. As fas as we know,
there have been no reports on the production of nitrile-
inserted compounds like 4 by the pyrolysis of arenediazo-
nium bis(tri¯uoromethanesulfonyl)methide [1], arenediazo-
spectra were recorded on a Varian Gemini 300 instrument
using CFCl3 (d 0) and Me4Si (d 0) as internal stan-
dards, respectively, and CDCl3 as a lock solvent. Low-
resolution mass spectra were obtained by direct insertion
for CI (isobutane) on a Shimadzu GC-MS instrument (GC-
17A and QP-5000). Elemental analyses were performed at
the School of Agriculture, Nagoya University.
3.1. Preparation of benzenediazonium
bis(trifluoromethanesulfonyl)methide (1)
Zhu's procedure [1] was modi®ed as follows: A solution
consisting of water (5 ml) and pottasium bis(tri¯uorometha-
nesulfonyl)methide (1.3 mmol), synthesized from the reac-
tion of bis(tri¯uoromethanesulfonyl)methane (0.136 g,
1.3 mmol) with potassium carbonate (0.09 g, 0.65 mmol),
was added dropwise to a 10 ml schlenk ¯ask charged with a
solution of phenyldiazonium chloride in water prepared by
treatment of aniline (130 ml, 1.4 mmol), water (0.5 ml),
hydrochloric acid (1 M, 3.1 ml) and sodium nitrite
(0.11 g, 1.56 mmol) at 38C (ice water±NaCl bath). After
being stirred at 38C for 0.5 h, the reaction mixture was
warmed to room temperature and stirred for 1 h. The light
brown precipitate was ®ltered off, washed with water (2 ml),
and dried under vacuum at ambient temperature to give the
pure product (0.35 g, 70% yield). Mp. 748C (decd.); IR
(KBr) 3098 (s), 2307 (s), 1574 (s), 1464 (m), 1350 (vs), 1333
(vs), 1314 (s), 1246 (m), 1167 (vs), 1101 (vs), 965 (vs), 930
nium tris(tri¯uoromethanesulfonyl)methide
arenediazonium bis(tri¯uoromethanesulfonyl)imide [4].
[4], or
(4)
The pyrolysis of 1 in dry acetone gave phenol and
bis(tri¯uoromethanesulfonyl)methane in quantitative yields,
respectively (Eq. (5)). In this reaction, 2-pheoxypropene as
an intermediate may be generated by nucleophilic attack of
the oxygen atom in acetone to phenyl cation formed.
(w), 849 (w), 752 (s), 664 (m), 637 (w), 604 (vs), 563 (m),
1
527 (m), 504 (s) cm
;
1H NMR (CDCl3 CD3OD,
300 MHz) d 7.94 (t, J 8 Hz, 2H), 8.25 (t, J 8 Hz,
1H), 8.36 (d, J 8 Hz, 2H); 19F NMR (CDCl3
CD3OD, 282 MHz) d 80.6.
3.2. Preparation of compound 2 by photolysis of
phenyliodobenzene bis(trifluoromethanesulfonyl)methide
(5)
In conclusion, phenyl[bis(tri¯uoromethanesulfonyl)]-
methane 2 was never be able to be obtained in isolatable
yield by the pyrolysis of 1 despite Zhu's report of success in
1993 [1]; its isomeric product 3 was obtained in good yield.
Compound 2 was prepared according to the known pro-
cedure [3]. White solid; mp. 1058C; TLC (hexane-EtOAc,
1:1), Rf 0:13; IR (KBr) 2950 (m), 1495 (w), 1458 (w),