Reactions of salicylaldehyde with tris(pentafluorophenyl)silanes and secondary amines

Article abstract of DOI:10.1007/s11172-006-0285-0

Reactions of tris(pentafluorophenyl)silanes RSi(C₆F ₅)₃ with salicylaldehyde and secondary amines were studied. The reactions afforded α-pentafluorophenyl-substituted amines. Silanes RSi(C₆F₅)₃ (R = Me, Ph, C ₆F₅, CH₂CH=CH₂, and CH=CH ₂) were found to be efficient reagents for transfer of the C ₆F₅ group to the iminium cation generated from salicylaldehyde and amine. However, tris(pentafluorophenyl)phenylethynyl-and tris(pentafluorophenyl)silanes were not able to serve as a source of a fluorinated substituent because of competitive transfer of acetylenide fragment or hydride.

Full text of DOI:10.1007/s11172-006-0285-0

Russian Chemical Bulletin, International Edition, Vol. 55, No. 3, pp. 517—522, March, 2006
517
Reactions of salicylaldehyde with tris(pentafluorophenyl)silanes
and secondary amines

A. D. Dilman, D. E. Arkhipov, P. A. Belyakov, M. I. Struchkova, and V. A. Tartakovsky
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
47 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (495) 135 5328. Eꢀmail: dilman@ioc.ac.ru
Reactions of tris(pentafluorophenyl)silanes RSi(C6F5)3 with salicylaldehyde and secondꢀ
ary amines were studied. The reactions afforded αꢀpentafluorophenylꢀsubstituted amines. Siꢀ
lanes RSi(C6F5)3 (R = Me, Ph, C6F5, CH2CH=CH2, and CH=CH2) were found to be
efficient reagents for transfer of the C6F5 group to the iminium cation generated from salicylꢀ
aldehyde and amine. However, tris(pentafluorophenyl)phenylethynylꢀ and tris(pentafluoroꢀ
phenyl)silanes were not able to serve as a source of a fluorinated substituent because of
competitive transfer of acetylenide fragment or hydride.
Key words: pentafluorophenylsilanes, salicylaldehyde, iminium cation, pentacoordinated
silicon, organofluorine compounds, amines, organosilicon compounds.
Amines containing a fluorinated substituent at the
αꢀcarbon atom are widely used in pharmaceutical indusꢀ
try and agrochemistry;1,2 however, the existing methods
for preparation of such compounds are very limited.3,4
Recently, we have proposed to synthesize amines conꢀ
taining a pentafluorophenyl fragment by threeꢀcomponent
coupling of aldehydes, amines, and methoxytris(pentaꢀ
fluorophenyl)silane as a source of the C6F5 group5
(Scheme 1).
As noted earlier,5 unlike MeOSi(C6F5)3, silanes havꢀ
ing only methyl and C6F5 groups at the Si atom (comꢀ
pounds with the general formula MenSi(C6F5)4–n
;
n = 1, 2, and 3) are inefficient reagents for threeꢀcompoꢀ
nent coupling with benzaldehyde and secondary amines.
We assumed that introduction into an aldehyde molecule
of an adjacent hydroxy group capable of binding to a silyl
reagent can promote an alternative mechanism, which in
turn would allow other C6F5ꢀcontaining silanes to be used.
For instance, a reaction of salicylaldehyde with silane is
expected to initially give silyl ether 1 (Scheme 2). Its
reaction with amine should generate zwitterionic interꢀ
mediate 2, which allows intramolecular transfer of the
nucleophilic C6F5 group from pentacoordinated Si atom
to the electrophilic iminium fragment. Hydrolysis of the
Si—O bond should finally give amine 3. At the same time,
possible transfer of the other substituent R1 in intermediꢀ
ate 2 can yield unwanted product 4. Dihydroxysilanes
(C6F5)(R1)Si(OH)2 and (C6F5)2Si(OH)2 formed upon the
hydrolysis of the intermediate silyl ethers will either
oligomerize through the Si—OH bonds or undergo cleavꢀ
age of the Si—C6F5 bond.
Scheme 1
Various pentafluorophenylsilanes were used in coupꢀ
ling reactions with salicylaldehyde (5) and pyrrolꢀ
idine (6) as model substrates (Scheme 3). The reacꢀ
tions were carried out in dichloromethane at room temꢀ
perature. It turned out that amine 3a is obtained in
high yield only with Si(C6F5)4 and MeSi(C6F5)3; in the
reaction with MeSi(C6F5)3, no product of methyl transꢀ
fer was detected. Although the standard reaction time
was 16 h, the reaction with MeSi(C6F5)3 was completed
R1 = Ph, 1ꢀnaphthyl, 2ꢀfurfuryl, Pri
R22 = (CH2)4, (CH2)5; R2 = Et, Bn
However, MeOSi(C6F5)3 tends to be hydrolyzed and
is difficult to prepare, which puts some limits on the pracꢀ
tical feasibility of this procedure. Here we present the
results of investigations aimed at searching for more conꢀ
venient perfluorophenylsilyl derivatives for the synthesis
of αꢀC6F5ꢀsubstituted amines.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 498—503, March, 2006.
1066ꢀ5285/06/5503ꢀ0517 © 2006 Springer Science+Business Media, Inc.

518
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 3, March, 2006
Dilman et al.
Scheme 2
R1 = H, Me, Ph, CH2CH=CH2, PhC≡C; R2 = Et, Bn, CH2=CHCH2; R22 = (CH2)4, (CH2)5
Scheme 3
One can assume that the influence of the orthoꢀhydrꢀ
oxy group is due to the mesomeric effect. For compariꢀ
son, we carried out a reaction of MeSi(C6F5)3 and
pyrrolidine with 2ꢀmethoxybenzaldehyde, which cannot
form silyl ether 1. The reaction occurred very slowly and
the target product was obtained over 47 h only in 40%
yield (Scheme 3). The mechanism shown in Scheme 1
was additionally confirmed by NMR monitoring of a reꢀ
action of salicylaldehyde with MeSi(C6F5)3 in CDCl3.
For instance, in the absence of an amine, the reagents
remained unchanged for a long period of time; however,
addition of triethylamine resulted in the disappearance of
the aldehyde and the formation of pentafluorobenzene
(1H and 19F NMR data). The reaction of salicylaldehyde
with silane probably involves deprotonation of the hydroxy
group followed by an attack of the aryloxide anion on the
Si atom and protonation of the pentacoordinate species at
the C6F5 group with elimination of pentafluorobenzene
(Scheme 4).
We also carried out reactions of other tris(pentaꢀ
fluorophenyl)silyl derivatives with salicylaldehyde under
standard conditions (CH2Cl2, 20 °C, 16 h). The reaction
with a silane containing the phenylethynyl fragment gave
a mixture of products due to transfer of both the C6F5
group and the phenylacetylenide substituent (Scheme 5).
The reaction with the silane HSi(C6F5)3 yielded a mixꢀ
ture of three products corresponding to the transfer of the
hydride ion and the C6F5 group to both the iminium
n
0
1
Yield of 3a (%)
n
2
3
Yield of 3a (%)
85
80
<5
<5
i. CH2Cl2, 20 °C, 16 h. ii. CH2Cl2, 20 °C, 47 h
substantially faster: the yield of amine 3a was 73%
even in 1 h.

Tris(pentafluorophenyl)silanes
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 3, March, 2006
519
Scheme 4
products in the reaction with CH2=CHCH2Si(C6F5)3 was
absolutely unexpected; indeed, it is known9 that allylꢀ
silanes can serve as efficient allylation reagents, also in
baseꢀcatalyzed processes involving fiveꢀcoordinate siliꢀ
con intermediates. For instance, allyl(trimethyl)silane reꢀ
acts with benzaldehyde in the presence of tetrabutylꢀ
ammonium fluoride to give the corresponding 1ꢀphenylꢀ
butꢀ3ꢀenꢀ1ꢀol.10 We carried out an analogous reaction of
benzaldehyde with CH2=CHCH2Si(C6F5)3 and obtained
2,3,4,5,6ꢀpentafluorobenzhydrol (8) as the sole product
in 74% yield (Scheme 5).
The following conclusion about the relative migrating
ability can be drawn from the data obtained: under nuꢀ
cleophilic assistance conditions, a group with the most
polar Si—C bond migrates most easily. At the same time,
hydrosilanes are more reactive than carbon derivatives,
probably because of the low steric requirements of the
hydride ion.
From the synthetic viewpoint, the optimum fluoriꢀ
nated silane is MeSi(C6F5)3 since this reagent, first, proꢀ
vides a high yield of pentafluorophenylꢀcontaining amine,
second, is convenient to handle (waterꢀresistant), third,
is easily accessible (prepared in one step from inexpensive
precursors11), and, fourth, the transfer of the methyl group
is highly improbable because the Si—Me bond is only
slightly polarized.
R1 = Me, Ph; R3N = pyrrolidine, NEt3
cation and salicylaldehyde. The formation of compounds
4a, 4b, and 7 is not surprising since it is known that
acetylenide and hydride ions in the presence of Lewis
bases can be transferred from silicon to an electroꢀ
philic site.6—8
Scheme 5
Various secondary amines can be involved in the reꢀ
action with salicylaldehyde and MeSi(C6F5)3 to give
threeꢀcomponent coupling products in 38—74% yield
(Scheme 6, Table 1). In the case of morpholine, the reacꢀ
tion rate was substantially lower; this is probably associꢀ
ated with the electronꢀwithdrawing effect of the O atom,
which destabilizes the iminium cation. However, the reꢀ
action accelerated when more polar acetonitrile was used
as a solvent. In some cases, diol 9 (~10—15%) was obꢀ
tained as a byꢀproduct due to the transfer of the C6F5
group to salicylaldehyde*. In the presence of acetic acid
(1 equiv.), this process was appreciably suppressed (<5%).
Scheme 6
i. CH2Cl2, 20 °C, 16 h
The coupling reactions of CH2=CHSi(C6F5)3,
PhSi(C6F5)3, and CH2=CHCH2Si(C6F5)3 with salicylalꢀ
dehyde and pyrrolidine also gave amine 3a in 62—84%
yield; no products due to transfer of the vinyl, phenyl,
and allyl groups were detected. The absence of allylation
Thus, we studied the reactions of pentafluorophenylꢀ
silanes with salicylaldehyde and secondary amines and
* A pure sample of diol 9 was obtained from salicylaldehyde and
MeSi(C6F5)3 in the presence of sodium acetate.

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Dilman et al.
Table 1. Reactions of salicylaldehyde with amines and
MeSi(C6F5)3
5.31 (s, 1 H, CH); 6.87—6.95 (m, 2 H, CHAr); 7.26 (td, 1 H,
CHAr, J = 7.7 Hz, J = 1.5 Hz); 7.36—7.43, 7.55—7.62 (both m,
3 H each, CHAr); 11.02 (s, 1 H, OH). 13C NMR (CDCl3), δ:
23.9 (CH2); 49.0 and 57.0 (CH and CH2N); 83.0 and 89.1
(C≡C); 116.3 (CHAr); 119.0 (CHAr); 122.2 (CAripso); 122.6
(CAripso); 127.9 (CHAr); 128.4 (CHAr); 128.6 (CHAr); 129.4
(CHAr); 131.9 (CHAr); 157.6 (CArOH).
Amine
Conditionsa Product Yield
(%)
Morpholine
CH2Cl2, 12 days
MeCN, 66 h
MeCN, 16 h
MeCN, 12 hb
MeCN, 7 daysb
MeCN, 21 hb
MeCN, 7 daysb
MeCN, 21 hb
3b
3b
3с
3d
3e
3e
3f
74
56
70
64
57
47
48
38
The reaction of salicylaldehyde with pyrrolidine and
HSi(C6F5)3 according to procedure A gave a mixture of comꢀ
pounds 3a (3%), 4b (44%), and 7 (25%). The yields were deterꢀ
Piperidine
Et2NH
(CH2=CHCH2)2NH
1
mined by quantitative H NMR spectroscopy with toluene as a
standard. The resulting mixture was dissolved with heating in
CCl4 (2 mL) and kept at room temperature for 24 h. The crystals
that formed were filtered off and recrystallized from hexane to
give diol 7 (18 mg). The combined filtrates were concentrated
and chromatographed on silica gel. Gradient elution in LP—ethyl
acetate (from 10 : 1 to 1 : 4), then in ethyl acetate, and finally in
ethyl acetate—MeOH (20 : 1) afforded amino phenol 4b (70 mg).
2ꢀ(Pyrrolidinꢀ1ꢀylmethyl)phenol (4b),13 Rf 0.37 (LP—ethyl
acetate, 1 : 4). 1H NMR (CDCl3), δ: 1.78—1.90 (m, 4 H,
(CH2)2); 2.56—2.69 (m, 4 H, CH2N); 3.82 (s, 2 H, CH2Ar);
6.76 (t, 1 H, CHAr, J = 7.2 Hz); 6.80 (d, 1 H, CHAr, J = 7.8 Hz);
6.98 (d, 1 H, CHAr, J = 7.2 Hz); 7.16 (t, 1 H, CHAr, J = 7.8 Hz);
10.92 (s, 1 H, OH). 13C NMR (CDCl3), δ: 23.7 ((CH2)2); 53.5
and 58.9 (CH2Ar and CH2N); 115.9 (CHAr); 118.8 (CHAr);
122.5 (CAripso); 127.8 (CHAr); 128.5 (CHAr); 158.1 (CArOH).
2ꢀHydroxymethylphenol (7), m.p. 83—85 °C (from LP)
(cf. Ref. 14: m.p. 82.5—83.5 °C).
2,3,4,5,6ꢀPentafluorobenzhydrol (8). A 0.75 M solution of
Bu4NF (0.73 mL, 0.55 mmol) in THF was added at –78 °C to a
solution of CH2=CHCH2Si(C6F5)3 (311 mg, 0.55 mmol) and
benzaldehyde (55 µL, 0.55 mmol) in THF (2 mL). The reaction
mixture was kept at –78 °C for 1 h and then at ~20 °C for an
additional 1.5 h. Then it was diluted with ether (15 mL) and
washed with water (10 mL). The product from the aqueous
phase was extracted with ether (2×10 mL). The combined orꢀ
ganic phase was dried with MgSO4, filtered through Celite, and
concentrated in vacuo. The residue was chromatographed on
silica gel in LP—ethyl acetate (from 20 : 1 to 5 : 1), Rf 0.10
(LP—ethyl acetate, 15 : 1). The yield of compound 8 was 100 mg
(74%), m.p. 42—47 °C (cf. Ref. 15: m.p. 49 °C).
Reactions of salicylaldehyde with amines and MeSi(C6F5)3
(procedure B). Salicylaldehyde (105 µL, 1 mmol) and an amine
(1 mmol) were added at 0 °C to a solution of MeSi(C6F5)3
(544 mg, 1 mmol) in MeCN (2.6 mL) (in the synthesis of comꢀ
pounds 3d—f, AcOH (57 µL, 1 mmol) was also added). The
reaction mixture was kept at ~20 °C (see Table 1). A satuꢀ
rated solution of Na2CO3 (0.3 mL) was added at 0 °C. The
reaction mixture was allowed to warm, diluted with LP—Et2O
(1 : 1; 10 mL), dried with Na2SO4, and filtered. Volatile subꢀ
stances were removed in vacuo. The residue containing products
3 and salicylaldehyde (10—20%) was separated by chromatoꢀ
graphy.
2ꢀ[Morpholino(pentafluorophenyl)methyl]phenol (3b) was obꢀ
tained according to procedure B in CH2Cl2 and isolated by
chromatography on silica gel in LP—ethyl acetate (from 20 : 1
to 6 : 1). The yield of compound 3b was 133 mg (74%), Rf 0.20
(LP—ethyl acetate, 6 : 1), m.p. 90—92 °C (from LP). Found (%):
C, 56.94; H, 3.91; N, 3.87. C17H14F5NO2 (359.29). Calcuꢀ
lated (%): C, 56.83; H, 3.93; N, 3.90. 1H NMR (CDCl3), δ:
2.47—2.72 (m, 4 H, N(CH2)2); 3.81 (t, 4 H, O(CH2)2, J =
Bn2NH
3f
a At 20 °C.
b In the presence of AcOH (1 equiv.).
demonstrated that MeSi(C6F5)3 is the optimum starting
reagent for the synthesis of amines containing the (2ꢀhydrꢀ
oxyphenyl)(pentafluorophenyl)methyl substituent.
Experimental
1
H, 13C, and 19F NMR spectra were recorded on Bruker
AMꢀ300, Bruker WMꢀ250, or Bruker ACꢀ200 instruments
in CDCl3. Silanes RSi(C6F5)3 (R = Me, Ph, CH=CH2,
CH2CH=CH2, and PhC≡C) (see Ref. 11) and HSi(C6F5)3 (see
Ref. 12) were prepared according to known procedures. Comꢀ
mercial salicylaldehyde and secondary amines (Acros and
Aldrich) were used. Freshly distilled (over CaH2) dichloroꢀ
methane was employed. Acetonitrile was distilled over CaH2
and kept over molecular sieves (4 Å). Distilled light petroleum
(LP, 60—70 °C) and ethyl acetate were used for chromatoꢀ
graphy.
Reactions of salicylaldehyde with pyrrolidine and RSi(C6F5)3
(procedure A). Salicylaldehyde (105 µL, 1 mmol) and pyrrolidine
(82 µL, 1 mmol) were added at 0 °C to a solution of RSi(C6F5)3
(1 mmol) in CH2Cl2 (2.6 mL). The reaction mixture was kept at
~20 °C for 16 h. A solution of NH4F (74 mg, 2 mmol) in MeOH
(1.3 mL) and water (0.2 mL) was added at 0 °C. The reaction
mixture was allowed to warm, diluted with LP—Et2O (1 : 1;
10 mL), dried with Na2SO4, and filtered. Volatile substances
were removed in vacuo and the residue was chromatographed on
silica gel.
2ꢀ[Pentafluorophenyl(pyrrolidinꢀ1ꢀyl)methyl]phenol (3a) (see
Ref. 5) was isolated by chromatography in LP—ethyl acetate
(18 : 1), Rf 0.31 (LP—ethyl acetate, 10 : 1). Compound 3a was
obtained according to procedure A from Si(C6F5)4 (85%),
MeSi(C6F5)3 (80%), CH2=CHSi(C6F5)3 (62%), PhSi(C6F5)3
(68%), and CH2=CHCH2Si(C6F5)3 (84%).
The reaction with PhC≡CSi(C6F5)3 according to procedure A
yielded a mixture of products 3a and 4a. Chromatography in
LP—ethyl acetate (from 20 : 1 to 10 : 1) afforded compounds 3a
(195 mg, 57%) and 4a (90 mg, 32%).
2ꢀ[3ꢀPhenylꢀ1ꢀ(pyrrolidinꢀ1ꢀyl)propꢀ2ꢀynꢀ1ꢀyl]phenol (4a),
Rf 0.21 (LP—ethyl acetate, 10 : 1), m.p. 73—75 °C (from LP).
Found (%): C, 82.39; H, 6.98; N, 5.01. C19H19NO (277.36).
Calculated (%): C, 82.28; H, 6.90; N, 5.05. 1H NMR (CDCl3),
δ: 1.87—1.96 (m, 4 H, (CH2)2); 2.81—2.99 (m, 4 H, 2 CH2N);

Tris(pentafluorophenyl)silanes
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 3, March, 2006
521
4.6 Hz); 5.31 (s, 1 H, CH); 6.71—6.79 (m, 1 H, CHAr);
6.81—6.93 (m, 2 H, CHAr); 7.13—7.22 (m, 1 H, CHAr); 10.97
(s, 1 H, OH). 13C NMR (CDCl3), δ: 51.4 (CH2N); 64.3 (CH);
66.7 (CH2O); 111.4 (tm, CC F ipso, J = 16.0 Hz); 117.2 (CHAr);
119.4 (CAripso); 119.5 (CHAr); 128.5 (CHAr); 129.6 (CHAr); 137.9
(dm, CF, J = 253 Hz); 141.0 (dm, CF, J = 256 Hz); 145.2 (dm,
CF, J = 249 Hz); 156.8 (CAr—OH). 19F NMR (CDCl3),
δ: –161.3 (td, mꢀF, J = 21.5 Hz, J = 8.3 Hz); –154.0 (t, pꢀF, J =
(tm, CC F ipso, J = 16.8 Hz); 117.2 (CHAr); 119.3 (CHAr); 120.1
5
(CH2=)6; 120.3 (CiꢀAr); 128.1 (CHAr); 129.5 (CHAr); 132.8
(CH=); 137.9 (dm, CF, J = 253 Hz); 141.0 (dm, CF, J =
256 Hz); 145.6 (dm, CF, J = 244 Hz); 157.4 (CArOH). 19F NMR
(CDCl3), δ: –161.4 (td, mꢀF, J = 21.1 Hz, J = 6.9 Hz); –153.6
6
5
(t, pꢀF, J = 21.1 Hz); –134.6 (br.m, oꢀF, ∆ν = 200 Hz).
1/2
2ꢀ[N,NꢀDibenzylamino(pentafluorophenyl)methyl]phenol (3f)
was obtained according to procedure B and isolated by chromaꢀ
tography in LP—ethyl acetate (10 : 1), Rf 0.33 (LP—ethyl acꢀ
etate, 4 : 1). Found (%): C, 68.91; H, 4.47; N, 2.71. C27H20F5NO
21.5 Hz); –137.9 (br.m, oꢀF, ∆ν = 460 Hz).
1/2
For efficient separation of compounds 3c—f from the
unreacted salicylaldehyde, the crude product was oximated prior
to chromatography: NH2OH•HCl (35 mg, 0.5 mmol) and
AcONa (41 mg, 0.5 mmol) were added to a solution of the crude
mixture in MeOH (1 mL). The reaction mixture was kept at
room temperature for 30 min, diluted with LP—Et2O (1 : 1;
10 mL), poured into water (20 mL), and washed with ether
(2×15 mL). The combined organic phase was dried with Na2SO4
and concentrated in vacuo.
1
(469.45). Calculated (%): C, 69.08; H, 4.29; N, 2.98. H NMR
(CDCl3), δ: 3.58 (d, 2 H, 2 CHAHBN, J = 13.4 Hz); 4.00 (d,
2 H, 2 CHAHBN, J = 13.4 Hz); 5.80 (s, 1 H, CH); 6.81—6.92
(m, 2 H, CHAr); 7.05 (d, 1 H, CHAr, J = 7.7 Hz); 7.26—7.47 (m,
11 H, CHAr); 11.30 (s, 1 H, OH). 13C NMR (CDCl3), δ: 55.2
(CH2); 59.6 (CH); 111.0 (tm, CC F ipso, J = 16.6 Hz); 117.2
6
5
(CHAr); 119.5 (CHAr); 120.4 (CAripso); 127.9 (CHAr); 128.2
(CHAr); 128.7 (CHAr); 129.5 (CHAr); 129.7 (CHAr); 136.5
(CAripso); 138.0 (dm, CF, J = 253 Hz); 141.1 (dm, CF, J =
256 Hz); 145.6 (dm, CF, J = 246 Hz); 157.1 (CArOH). 19F NMR
(CDCl3), δ: –161.4 (td, mꢀF, J = 21.5 Hz, J = 7.6 Hz); –153.6
(t, pꢀF, J = 21.5 Hz); –134.6 (br.m, oꢀF, ∆ν1/2 = 190 Hz).
2´ꢀHydroxyꢀ2,3,4,5,6ꢀpentafluorobenzhydrol (9). A mixture
of MeSi(C6F5)3 (544 mg, 1 mmol), salicylaldehyde (105 µL,
1 mmol), and sodium acetate (98 mg, 1.2 mmol) in THF (2 mL)
was refluxed for 2 h. A solution of NH4F (74 mg, 2 mmol) in
MeOH (1.3 mL) and water (0.2 mL) was added at 0 °C. The
mixture was allowed to warm, diluted with Et2O (10 mL), dried
with Na2SO4, and filtered. Volatile substances were removed
in vacuo. The residue was chromatographed on silica gel in
LP—ethyl acetate (from 10 : 1 to 4 : 1), Rf 0.16 (LP—ethyl acꢀ
etate, 3 : 1). The yield of compound 9 was 247 mg (85%), m.p.
74—77 °C (from LP). Found (%): C, 53.94; H, 2.27. C13H7F5O2
(290.19). Calculated (%): C, 53.81; H, 2.43. 1H NMR (CDCl3),
δ: 6.47 (s, 1 H, CH); 6.84 (d, 1 H, CHAr, J = 8.1 Hz); 6.89 (d,
1 H, CHAr, J = 7.7 Hz); 6.96 (d, 1 H, CHAr, J = 7.7 Hz); 7.21 (t,
1 H, CHAr, J = 7.9 Hz). 13C NMR (CDCl3), δ: 66.8 (CH); 115.6
(tm, CC F ipso, J = 16.3 Hz); 116.9 (CHAr); 120.6 (CHAr); 123.9
2ꢀ[Pentafluorophenyl(piperidino)methyl]phenol (3c) was obꢀ
tained according to procedure B and isolated by chromatography
in LP—ethyl acetate (20 : 1), Rf 0.42 (LP—ethyl acetate, 10 : 1).
Found (%): C, 60.48; H, 4.44; N, 3.68. C18H16F5NO (357.32).
Calculated (%): C, 60.50; H, 4.51; N, 3.92. 1H NMR (CDCl3),
δ: 1.41—1.59 (m, 2 H), 1.62—1.81 (m, 4 H), 3 CH2; 2.54 (br.m,
4 H, 2 CH2N, ∆ν1/2 = 22 Hz); 5.42 (s, 1 H, CH); 6.66—6.89 (m,
3 H, CHAr); 7.16 (t, 1 H, CHAr, J = 7.5 Hz); 11.78 (s, 1 H, OH).
13C NMR (CDCl3), δ: 23.8 (CH2); 26.0 (CH2); 51.7 (br.m,
CH2N, ∆ν
= 19 Hz); 64.0 (CH); 111.1 (tm, CC F ipso, J =
1/2
6 5
16.3 Hz); 117.0 (CHAr); 118.9 (CHAr); 120.0 (CAripso); 127.9
(CHAr); 129.2 (CHAr); 137.8 (dm, CF, J = 252 Hz); 140.8 (dm,
CF, J = 256 Hz); 145.2 (dm, CF, J = 245 Hz); 157.6 (CArOH).
19F NMR (CDCl3), δ: –161.8 (td, mꢀF, J = 21.9 Hz, J =
8.3 Hz); –154.6 (t, pꢀF, J = 21.9 Hz); –141.1 (br.m, oꢀF,
∆ν1/2 = 340 Hz); –132.6 (br.m, oꢀF, ∆ν1/2 = 340 Hz).
2ꢀ[N,NꢀDiethylamino(pentafluorophenyl)methyl]phenol (3d)
was obtained according to procedure B and isolated by chromaꢀ
tography in LP—ethyl acetate (25 : 1), Rf 0.42 (LP—ethyl
acetate, 10 : 1). Found (%): C, 59.19; H, 4.71; N, 4.17.
C17H16F5NO (345.31). Calculated (%): C, 59.13; H, 4.67;
N, 4.06. 1H NMR (CDCl3), δ: 1.12—1.35 (t, 6 H, Me, J =
7.1 Hz); 2.35—2.61 (m, 2 H, 2 CHAHBN); 2.79—3.02 (m, 2 H,
2 CHAHBN); 5.75 (s, 1 H, CH); 6.68—6.95 (m, 3 H, CHAr);
7.13—7.24 (m, 1 H, CHAr); 11.80 (s, 1 H, OH). 13C NMR
(CDCl3), δ: 11.6 (Me); 43.3 (CH2); 59.3 (CH); 111.3 (tm,
6
5
(CAripso); 126.8 (CHAr); 129.8 (CHAr); 137.7 (dm, CF, J =
254 Hz); 141.0 (dm, CF, J = 259 Hz); 144.8 (dm, CF, J =
246 Hz); 154.2 (CAr—OH). 19F NMR (CDCl3), δ: –162.4 (td,
mꢀF, J = 21.1 Hz, J = 6.9 Hz); –155.0 (t, pꢀF, J = 21.1 Hz);
–143.3 (dd, oꢀF, J = 21.1 Hz, J = 6.9 Hz).
1ꢀ[(2ꢀMethoxyphenyl)(pentafluorophenyl)methyl]pyrrolidine
was obtained from 2ꢀmethoxybenzaldehyde according to proceꢀ
dure B (40 h) in CH2Cl2 and isolated by chromatography in
LP—ethyl acetate (27 : 1), Rf 0.37 (LP—ethyl acetate, 10 : 1).
The yield was 284 mg (40%). Found (%): C, 60.37; H, 4.46;
N, 3.98. C18H16F5NO (357.32). Calculated (%): C, 60.50;
H, 4.51; N, 3.92. 1H NMR (CDCl3), δ: 1.79—1.89 (m, 4 H,
(CH2)2); 2.32—2.42 (m, 2 H, 2 CHAHBN); 2.62—2.73 (m, 2 H,
2 CHAHBN); 3.76 (d, 3 H, OCH3, J = 1.5 Hz); 5.15 (s, 1 H,
CC F ipso, J = 16.6 Hz); 117.0 (CHAr); 119.0 (CHAr); 120.5
5
(CA6ripso); 127.9 (CHAr); 129.2 (CHAr); 137.9 (dm, CF, J =
253 Hz); 140.9 (dm, CF, J = 256 Hz); 145.7 (dm, CF, J =
243 Hz); 157.8 (CArOH). 19F NMR (CDCl3), δ: –161.6 (td,
mꢀF, J = 21.8 Hz, J = 6.9 Hz); –154.4 (t, pꢀF, J = 21.8 Hz);
–136.0 (br.m, oꢀF, ∆ν = 1400 Hz).
1/2
2ꢀ[N,NꢀDiallylamino(pentafluorophenyl)methyl]phenol (3e)
was obtained according to procedure B and isolated by chromaꢀ
tography in LP—ethyl acetate (10 : 1), Rf 0.79 (LP—ethyl acꢀ
etate, 3 : 1). Found (%): C, 61.84; H, 4.46; N, 3.52. C19H16F5NO
CH); 6.81 (d, 1 H, CHAr, J = 8.7 Hz; J = 7.0 Hz) (t, 1 H, CHAr
,
J = 7.5 Hz); 7.20—7.25, 7.84—7.90 (both m, 1 H each, CHAr).
13C NMR (CDCl3), δ: 23.6 (CH2); 53.6 (CH2N); 55.1 and 57.6
1
(369.33). Calculated (%): C, 61.79; H, 4.37; N, 3.79. H NMR
(CDCl3), δ: 3.04 (dd, 2 H, 2 CHAHBN, J = 14.0 Hz, J =
7.4 Hz); 3.47 (dd, 2 H, 2 CHAHBN, J = 14.0 Hz, J = 5.9 Hz);
5.13—5.31 (m, 4 H, CH=CH2); 5.71 (s, 1 H, CHN); 5.83—5.99
(m, 2 H, CH=CH2); 6.70—6.83 (m, 2 H, CHAr); 6.88 (d, 1 H,
CHAr, J = 8.5 Hz); 7.19 (t, 1 H, CHAr, J = 7.5 Hz); 11.23 (s,
1 H, OH). 13C NMR (CDCl3), δ: 52.9 (CH2); 59.5 (CH); 111.5
(CH and OMe); 110.1 (CHAr); 116.5 (tm, CC F ipso, J = 16.7 Hz);
6
120.3 (CHAr); 127.9 (CAripso); 128.3 (CHAr); 1259.3 (CHAr); 137.4
(dm, CF, J = 251 Hz); 140.3 (dm, CF, J = 258 Hz); 145.4 (dm,
CF, J = 250 Hz); 156.6 (COMeipso). 19F NMR (CDCl3), δ: –164.4
(td, mꢀF, J = 21.2 Hz, J = 6.9 Hz); –158.2 (t, pꢀF, J = 21.2 Hz);
–141.0 (br.d, oꢀF).

522
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 3, March, 2006
Dilman et al.
7. A. Hosomi, H. Hayashida, S. Kohra, and Y. Tominaga,
J. Chem. Soc., Chem. Commun., 1986, 1411.
8. C. Chuit, R. J. P. Corriu, C. Reye, and J. C. Young, Chem.
Rev., 1993, 93, 1371.
9. S. Rendler and M. Oestreich, Synthesis, 2005, 1727.
10. A. Hosomi, A. Shirahata, and H. Sakurai, Tetrahedron Lett.,
1978, 3043.
11. A. D. Dilman, D. E. Arkhipov, A. A. Korlyukov, V. P.
Ananikov, V. M. Danilenko, and V. A. Tartakovsky,
J. Organomet. Chem., 2005, 690, 3680.
This work was financially supported by the Ministry of
Education and Science (MKꢀ2235.2005.3), the Internaꢀ
tional Association for the Promotion of Cooperation with
Scientists from the New Independent States of the Former
Soviet Union (2003ꢀ55ꢀ1185), and the Russian Academy
of Sciences (Program No. 8 of the Presidium of the Rusꢀ
sian Academy of Sciences).
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Received March 9, 2006