Electrophilic animation of organozinc reagents with acetone O-(2,4,6-trimethylphenylsulfonyl)oxime and O-methylhydroxylamine

Article abstract of DOI:10.1039/a906093f

Reaction of diorganozincs and triorganozincates with acetone O-(2,4,6-trimethylphenylsulfonyl)oxime or O-methylhydroxylamine in the presence of CuCN provides a new one-flask method for electrophilic amination of organozinc reagents. Considering the lithium- or magnesium-to-zinc transmetallation, this method also extends the scope of electrophilic amination of organolithiums and Grignard reagents. The Royal Society of Chemistry 1999.

Full text of DOI:10.1039/a906093f

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Electrophilic amination of organozinc reagents with
acetone O-(2,4,6-trimethylphenylsulfonyl)oxime and
O-methylhydroxylamine
Ender Erdik* and Tahir Da s¸ kapan
Ankara University, Science Faculty, Department of Chemistry, Be s¸ evler, Ankara 06100, Turkey
Received (in Cambridge, UK) 27th July 1999, Accepted 8th September 1999
Reaction of diorganozincs and triorganozincates with acetone O-(2,4,6-trimethylphenylsulfonyl)oxime or
O-methylhydroxylamine in the presence of CuCN provides a new one-flask method for electrophilic amination
of organozinc reagents. Considering the lithium- or magnesium-to-zinc transmetallation, this method also
extends the scope of electrophilic amination of organolithiums and Grignard reagents.
Introduction
The importance of amines and the commonplace use of
organometallic reagents in organic synthesis has created the
ϩ
need for ‘NH ’-containing reagents capable of C–N con-
2
nection. There are detailed reviews on the amination of
1
carbanions. In addition, a number of new reagents have
been recently developed, among them N,O-bis(trimethylsilyl)-
2
t
3
hydroxylamine, LiN(OTs)CO Bu (LiBTOC), N-protected
2
4
5
oxaziridines, 1-chloro-1-nitrosocyclohexane, acetone O-
2,4,6-trimethylphenylsulfonyl)oxime,
yl)benzophenone O-methyloxime and bis(2,2,2-trichloroethyl)
azodicarboxylate.
6
(
4,4Ј-bis(trifluorometh-
7
Scheme 1 Amination of organozinc species 1–6 with acetone O-(2,4,6-
trimethylphenylsulfonyl)oxime 7 and O-methylhydroxylamine 8.
8
Efficient methods are known for electrophilic amination
24
1a,3a–d,4,5,9
1a,6,7,9
We have reported in an earlier paper a simple and mild
method for electrophilic amination of diarylzincs and triaryl-
zincates with 7 and 8. In this paper, we explore the use of this
method.
of organolithiums,
coppers
Grignard reagents,
organo-
and organoboranes. However, to date, there
have been only some unsuccessful attempts on the amination
1a,2,3,8–10
11
1a,3e,8,9,12,13
of ordinary organozinc reagents
amination examples for zinc enolates.
and a few successful
Recently, two papers
3a,5,14
have appeared on the amination of organozinc reagents. In the
first, zinc cyanocuprates react with lithium amides and the
15
Results and discussion
formed zinc amidocyanocuprates, upon oxidation, decompose
At the initial stage of this investigation, we focused on the amin-
ation of phenylzinc species with 7 and 8 for determining the
optimal reaction conditions. Phenylzinc chloride 1a, diphenyl-
zinc 2a and lithium (or bromomagnesium) triphenylzincate
3a were prepared by transmetallation of the corresponding
phenyllithium or phenylmagnesium bromide with ZnCl2;
chlorozinc diphenylcuprate 4a and chlorozinc phenylcyano-
cuprate 5a were prepared by transmetallation of in situ
prepared lithium diphenylcuprate and lithium phenylcyano-
cuprate, respectively, with ZnCl2. Amination yields of
phenylzinc reagents 1a–6a with 7 and 8 are given in Table 1.
We observed that the reaction of phenylzinc chloride 1a,
diphenylzinc 2a, and triphenylzincate 3a with 7 takes place only
in the presence of CuCN, except a low-yield reaction of 3a with
8 (entry 7).
The reaction conditions were optimized by adding 1 mol
equiv. of aminating reagent 7 or 8 to 1.5 mol equiv. of
phenylzinc reagents 1a, 2a and phenyl zincate 3a or 2 mol equiv.
of zinc phenylcuprates 4a, 5a in diethyl ether or in diethyl
ether–THF at room temperature, resulting in almost complete
consumption of 7 or 8 within 3 h. Experiments indicated that
the yield is strongly dependent on the type of phenylzinc species
and on the amount of CuCN. The highest yield in the amin-
ation with 7 is obtained by treating triphenylzincate 3a in the
presence of 20 mol% CuCN (entry 9); however phenylzinc
chloride 1a and diphenylzinc 2a are also effective in CuCN-
mediated amination (entries 3 and 6). Carrying out the
16
to provide amines. In the second, the addition of organozinc
halides to di-tert-butyl azodicarboxylate (DBAD) is described
to give hydrazino derivatives, which give amines after the
removal of tert-butoxycarbonyl groups and then reductive
cleavage of the N–N bond.
17–20
The importance of organozinc reagents
due to their high
reactivity, easy preparation by Li- and Mg-to-Zn transmetal-
lation, and the use of electrophilic functional group-containing
reagents prompted us to investigate the electrophilic amination
of organozinc reagents. Since the major drawback related to
the use of organozinc reagents is the use of active zinc, the
work to be discussed here involves preparation of organozincs
by transmetallation, except for some functional group-
containing organozincs which are prepared by metallation of
organic halides. In our study, the reagents of choice for amin-
ation of organozincs are acetone O-(2,4,6-trimethylphenyl
sulfonyl)oxime and O-methylhydroxylamine (Scheme 1).
Acetone O-(2,4,6-trimethylphenylsulfonyl)oxime 7 has been
developed in our laboratories for amination of Grignard
19
6
reagents and reacts by displacement of the mesitylsulfonyl-
oxy group giving an imine, which upon hydrolysis provides
amines. O-Methylhydroxylamine and its methyllithium com-
plex have long been used successfully for amination of organo-
9
,21
9,21–23
9
lithiums,
Grignard reagents
and organocoppers and
9
once unsuccessfully for organozincs. Compound 7 can be more
easily prepared and conveniently stored than can 8.
J. Chem. Soc., Perkin Trans. 1, 1999, 3139–3142
This journal is © The Royal Society of Chemistry 1999
3139

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Table 1 Reactions of phenylzinc reagents 1a–6a with aminating
Table 2 Amination reactions of phenylmetals with 7 and 8
a
reagents 7 and 8
1
. THF, rt, 3 h
PhM ϩ 7 or 8
PhNH2
1
. THF, rt, 3 h
2. Hydrolysis
PhM ϩ 7 or 8
a–6a
PhNH2
2
. Hydrolysis
9
1
9
Yield of PhNH2
Aminating reagent
c
Yield of PhNH2
Aminating reagent
a
b,c
CuCN
(mol%)
Entry
M
Li
Li/‘CuI’
Li/‘CuI’
MgBr
MgBr/‘CuI’
Cu
7
8
b
Entry
PhM
7
8
d
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
6
91
37
83
e
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
PhZnCl 1a
PhZnCl 1a
PhZnCl 1a
PhZnCl 1a
0
0
7
22e
d
10
20
20
25(25 )
58
48
46
d
58
e
d, f
59e
Ph Zn 2a
Ph Zn 2a
0
44
0
56
2
f
e
20
82(82 )
33
1/2 CuLi
43e
2
Ph ZnLi 3a
Cu(CN)Li
1/3 CuLi2
1/2 Cu(CN)Li2
ZnCl/‘CuCN’
1/2 Zn/‘CuCN’
1/3 ZnM/‘CuCN’ (M = Li, MgBr)
1/2 CuZnCl
76
3
e
Ph ZnLi 3a
10
20
52
70
49
56
65(49 )
68(51 )
39e
3
g
f
Ph ZnLi 3a
95(89, 95 )
50(50 )
42(38 )
35
3
f
g
h
a
g
1
1
1
1
1
1
1
Ph CuZnCl 4a
58 (65 )
7
82
95
2
f
g
h
PhCu(CN)ZnCl 5a
PhZnCl 1a
44 (68 )
g h
f
20
20
20
20
20
70 (85 )
f
g
Ph Zn 2a
49
56
2
f
g
Ph ZnMgBr 3a
85(76 )
79(70 )
Cu(CN)ZnCl
b
3
h
f
Ph ZnLi 3a
a
3
GC yield. Aminating reagent is 8–methyllithium complex (refs. 9
Me PhZnLi 6a
59
c
d
e
2
and 22). Yield of benzanilide. Ref. 6a. Amination of phenylithium
(2 mol equiv.), phenylcopper (2 mol equiv.), lower- and higher-order
homocuprates (2 mol equiv.) and lower- and higher-order cyano-
cuprates (1 mol equiv.) with 7 (1 mol equiv.) was carried out in diethyl
ether at room temperature similar to amination of organozinc reagents
a
Reactions were carried out on 1.5 or 3.0 mmol aminating reagent 7 or
. PhM:7 = 1.5 and PhM:8 = 2 for 1a, 2a and 3a; PhM:7 (or 8) = 2 for
a and 5a. Phenylzinc reagents in entries 1–10, 15 and 16 were prepared
by Li-to-Zn transmetallation and in entries 11–14 by Mg-to-Zn trans-
8
4
b
c
f
metallation. Yield determined as average of two or more runs by GC
as explained in the Experimental section. Ref. 6a. The reaction time
decreases in CuI-mediated reaction. Organozinc reagent was prepared
by Li-to-Zn metallation (Table 1, entries 3, 6, 9). Organozinc reagent
was prepared by Mg-to-Zn metallation (Table 1, entries 12–14).
d
g
using internal standard technique and based on 7 or 8. Yield of aniline
e
f
h
purified by column chromatography. PhZnCl:7 = 4. Yield of aniline
g
h
isolated as benzanilide. Yield of aniline purified by distillation. 20
mol% MgCl was added.
2
zincate/CuCN (entry 13). Phenylmagnesium bromide/CuI
(entry 5) is not as effective as bromomagnesium triphenyl-
zincate/CuCN (entry 13). Concerning the available data for the
amination with 8, the most effective phenylmetals are phenyl-
lithium (entry 1) and lithium triphenylzincate/CuCN (entry 13).
Lithium diphenylcuprate and diphenylzinc/CuCN can also be
aminated in comparable high yields (entries 7 and 12, respect-
ively). From these results, it appears that transmetallation of
organolithiums to triorganozincates instead of organocyano-
cuprates seems to provide an alternative method in the amin-
ation with 7. However, transmetallation of Grignard reagents
to organozincates rather than organocuprates seems to be the
method of choice in the amination with either 7 or 8.
Having established a viable route to aminate organozincs
with acetone O-(2,4,6-trimethylphenylsulfonyl)oxime 7 and
with O-methylhydroxylamine 8; the scope and generality of the
amination protocol was examined for a series of organozincs
(Table 3). In amination with 7, yields of monoorganozincs 1
were tabulated in addition to diorganozincs 2 and triorgano-
zincates 3 since 1 and 2 are expected to give comparable yields
with 3; however, in amination with 8, yields of only 2 and 3 were
reported, except for 1a and 1e. These data show that amination
proceeds with medium yields for aryl, alkyl, cycloalkyl and
benzyl zinc reagents. However, to some degree, there are differ-
ences between the effectiveness of organozincs and aminating
reagents. For example, amination of p-ethoxycarbonylphenyl-
zinc bromide 1e with 8 resulted in a very low yield (entry 13);
and n-hexylzinc reagents 1f, 2f, 3f could not be aminated with
7 (entries 14–16). The mildness of the conditions involved
allow a certain tolerance for electron-rich functional groups on
arylzincs; however, attempts to aminate functional-group-
containing alkylzincs, for example, 4-chlorobutylzinc reagents
failed and products possibly formed after amination of organo-
zinc species were not identified.
amination of phenylzinc chloride with a 4:1 molar ratio of
1
a:7 did not give a comparable yield with 3a. The use of
dimethylphenylzincate 6a instead of triphenylzincate was not
found to be more successful for amination. These observations
seem identical with the fact that tetracoordinated zincates pre-
pared in situ from trioganozincates and anion species such as
CN have higher reactivity compared with the conventional
25
triorganozincates.
As seen, higher yields are obtained in the amination of
Grignard reagent-derived organozincs rather than lithium
reagent-derived organozincs (entries 3 and 12; 6 and 13; 9 and
1
4), supporting the role of MgCl as a Lewis acid in electro-
2
philic amination of carbanions with synthetic equivalents of
ϩ
6,26
the NH2 synthon.
In fact, CuCN-catalyzed amination of
lithium triphenylzincate with 7 led to a higher yield in the
presence of MgCl (20 mol%) (entries 9 and 15). Amination of
2
stoichiometric zinc diphenylcuprate 4a and zinc phenylcyano-
cuprate 5a did not give higher yields than amination of CuCN-
mediated zincates 3c and even phenylzinc chloride 1a.
Applying the same procedure to the amination of phenylzinc
reagents with 8, diphenylzinc 2a afforded a surprisingly higher
yield compared with the amination with 7 (entry 6) while
amination of phenylzinc chloride 1a did not take place. Lithium
triphenylzincate 3a was aminated almost in quantitative yield
(
entry 9).
In an effort to determine the most effective phenylmetal in
the amination with 7 and 8, we examined the relevant literature
data and we also carried out amination of phenyl-lithium and
-
copper reagents with 7 in addition to our amination studies of
phenyl Grignard reagents with 7 (Table 2). For comparison,
only lithium phenylcyanocuprate (entry 8) gives a yield com-
parable with that of the lithium triphenylzincate/CuCN system,
but not as high as the yield of bromomagnesium triphenyl-
3
140
J. Chem. Soc., Perkin Trans. 1, 1999, 3139–3142

View Article Online
Table 3 CuCN-mediated amination of organozinc reagents with
aminating reagents 7 and 8
spectra were recorded on a Unicam Mattson 1000 FT-IR
spectrometer as a KBr pellet, and wavenumbers of only the
strongest/structurally more important peaks are reported in
Ϫ1
1
1. CuCN (20 mol%), THF, rt, 3 h
a,b
cm . H NMR spectra were obtained in CDCl at 400
3
RM ϩ 7 or 8
–3
RNH2
2. Hydrolysis, rt, 3–4 h
MHz using a Bruker-GmbH DPX instrument. Chemical
1
9
shifts are reported in δ(ppm)-values relative to Me Si and,
4
for peak multiplicities, the following abbreviations are used:
s, singlet; d, doublet; t, triplet; q, quartet; br s, broad singlet;
m, multiplet.
M = ZnCl (or ZnBr), 1/2 Zn, 1/3 ZnMgBr
1
2
3
c
Diethyl ether and THF were distilled from sodium and
benzophenone ketyl under dry nitrogen. Magnesium turnings
for Grignard reactions (Fischer), lithium dispersion in mineral
oil (BDH), and zinc dust (Merck) were used without purifi-
cation. Zinc chloride (Aldrich) was dried under reduced pres-
sure (2 mmHg) at 100 ЊC for 2 h and dissolved in THF before
use. Magnesium chloride (BDH) was dried under nitrogen
Yield of RNH2
Aminating reagent
Entry
RM
C H ZnCl 1a
7
8
d
d
d
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
40
51
76
49
45
55
54
51
61
33
42
52
51
0
7
6
5
(C H ) Zn 2a
82
95
6
5
2
28
before use. Copper() iodide (Fischer) and copper() cyanide
(C H ) ZnMgBr 3a
6
5 3
29
(
Aldrich) were purified according to the published pro-
p-CH C H ZnCl 1b
3
6
4
(p-CH C H ) Zn 2b
62
70
cedures, dried at 60–90 ЊC under reduced pressure (1 mmHg)
for 4 h and kept under dry nitrogen. Phenyllithium and benzyl-
magnesium bromide were prepared in diethyl ether, and other
Grignard reagents were prepared in THF by conventional
standard methods found elsewhere. The concentration of
phenyllithium and Grignard reagents was found prior to use by
titration with sec-butyl alcohol using o-phenanthroline as an
3
6
4 2
(p-CH C H ) ZnMgBr 3b
3
6
4 3
p-CH OC H ZnCl 1c
3
6
4
(p-CH OC H ) Zn 2c
65
63
3
6
4 2
(p-CH OC H ) ZnMgBr 3c
3
6
4 3
1
1
1
1
1
1
1
1
1
1
2
2
2
p-BrC H ZnCl 1d
6 4
(p-BrC H ) Zn 2d
40
50
12
6
4 2
(p-BrC H ) ZnMgBr 3d
6
4 3
30
p-C H O CC H ZnBr 1e
indicator.
2
5
2
6
4
n-C H ZnCl 1f
6
13
Phenylcopper PhCu, lithium diphenylcuprate Ph CuLi, and
2
(n-C H ) Zn 2f
35
50
6
13 2
dilithium triphenylcuprate Ph CuLi were prepared by addition
3
2
(n-C H ) ZnMgBr 3f
0
12
10
42
20
56
62
6
13 3
of 1, 2 and 3 mol equiv. of phenyllithium, respectively, to a
c-C H ZnCl 1g
6
11
31
suspension of 1 mol equiv. of CuI in diethyl ether at 0 ЊC.
(c-C H ) Zn 2g
28
38
6
11 2
(c-C H ) ZnMgBr 3g
Lithium phenylcyanocuprate PhCu(CN)Li and dilithium
diphenylcyanocuprate Ph Cu(CN)Li were prepared by addi-
6
11 3
C H CH ZnCl 1h
6
5
2
2
2
(C H CH ) Zn 2h
50
61
6
5
2
3
tion of 1 and 2 mol equiv. of phenyllithium, respectively, to
(C H CH ) ZnMgBr 3h
2,31
6
5
2 3
a suspension of 1 mol equiv. of CuCN in THF at 0 ЊC.
a
32
Organozinc reagents 1, 2 and 3 were prepared by transmetallation of
corresponding Grignard reagents in THF (1, 2 and 3 mol equiv.,
Chlorozinc diphenylcuprate, Ph CuZnCl
and chlorozinc
were prepared by
2
15
phenylcyanocuprate PhCu(CN)ZnCl
respectively) with anhydrous ZnCl (1 mol equiv.) in THF. Organozinc
2
addition of in situ prepared 1 mol equiv. of lithium cuprates to
reagent 1e was prepared by metallation of the corresponding aryl
b
a 0.45 M solution of 1 mol equiv. of ZnCl in THF at 0 ЊC.
2
bromide with active Zn in diethyl ether. Reactions were carried out on
Carrying out the transmetallation reactions at Ϫ78 ЊC did not
produce any change in the reactivities of phenylcopper, phenyl-
lithium cuprates and phenylzinc cuprates in amination reac-
1
.5 or 3.0 mmol aminating reagent, 7 or 8, which was added to a
mixture of RM and CuCN in THF (RM:7 = 1.5 and RM:8 = 2.0).
c
d
Yield of amine isolated as N-benzoyl derivative. Organozinc reagents
1
(
, 2 and 3 were prepared by transmetallation of phenyllithium in Et O
1, 2 and 3 mol equiv., respectively) with anhydrous ZnCl (1 mol equiv.)
2
tions. Diorganozinc R Zn, organozinc chloride RZnCl, and
2
2
lithium triorganozincate (or bromomagnesium triorganozinc-
in THF.
ate) reagents R ZnM (M = Li or MgBr) were prepared by
3
addition of 2, 1 or 3 mol equiv. of organolithium or Grignard
reagent, respectively, to a 0.45 M solution of 1 mol equiv. of
Conclusions
19
ZnCl in THF at 0 ЊC. In transmetallation reactions, stirring
2
In summary, we have shown that one-flask and medium-yield
amination of aryl, functionalized aryl, alkyl and benzyl zinc
reagents with acetone O-(2,4,6-trimethylphenylsulfonyl)oxime
or with O-methylhydroxylamine is possible in the presence of
CuCN. This amination protocol also provides an alternative
method for electrophilic amination of organolithiums and
Grignard reagents, which can be easily transmetallated to
organozincs. Efforts to broaden the scope of our new amination
procedure and to develop other one-flask amination methods
for organozincs are currently in progress.
was continued (ca. 15–30 min) at 0 ЊC until the reaction mix-
tures became clear. p-(Ethoxycarbonyl)phenylzinc bromide 1e
was prepared from the corresponding aryl bromide by using
19
active zinc in THF.
Acetone O-(2,4,6-trimethylphenylsulfonyl)oxime
O-methylhydroxylamine 8 were prepared and purified accord-
33
7
and
34
ing to the published procedures.
Amination of organozinc reagents
Typical procedure for the CuCN-mediated amination of mono-
and di-organozinc and triorganozincate reagents 1–3 with
acetone O-(2,4,6-trimethylphenylsulfonyl)oxime 7 or O-methyl-
hydroxylamine 8 is given below.
Experimental
General conditions
All reactions were carried out under a positive pressure of dry
Under nitrogen atmosphere and at room temperature, to a
THF solution of an organozinc reagent (4.5 mmol) was added
CuCN (0.614 g, 0.90 mmol). (If the organozinc reagent was
prepared in situ by transmetallation of an organolithium or
Grignard reagent at 0 ЊC, the temperature was allowed to rise to
room temperature before the addition of CuCN.) After stirring
of the mixture for 15 min, a solution of 7 (0.765 g, 3.00 mmol)
27
nitrogen in oven-dried glassware. Reagents and solvents were
handled by using standard syringe–septum cap techniques.
Reactions were monitored by gas chromatography analysis of
reaction aliquots using a Perkin-Elmer F-11 gas chromato-
graph equipped with an SE-30 column. Analytical TLC
analysis was done on Merck silica gel plates. Chromatography
was performed on silica gel-60 using light petroleum (distil-
lation range 40–60 ЊC)–diethyl ether mixtures as eluent. IR
3
3
in THF (6 cm ) or 8 (0.047 g, 2.25 mmol) in THF (4 cm )
was added and stirring was continued for 3 h. For hydrolytic
J. Chem. Soc., Perkin Trans. 1, 1999, 3139–3142
3141

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work-up after amination with 7, the mixture was stirred at room
temperature with 12 M HCl (10 cm ) for 2 h. The aqueous
phase was washed with diethyl ether, made basic with conc.
References
3
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3
(
4 × 30 cm ). The organic layer was dried over Na SO . The
2
4
crude material obtained after evaporation of solvent in vacuo
was purified by distillation or flash chromatography on silica gel
with diethyl ether–light petroleum (5:4) to give pure amine 9
whose GC and spectral data matched those of authentic
material. After amination with 8, hydrolysis of the mixture was
2
3
A. Casarini, P. Dembech, D. Lazzari, E. Marini, G. Reginato,
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3
carried out with saturated aq. NH Cl–NH (5:1) (10 cm ). The
4
3
aqueous phase was extracted with diethyl ether and the crude
material was purified with column chromatography to give the
amine as above. For convenience in isolation, the product
amines were converted to their N-benzoyl derivatives by reac-
4
35
tion with benzoyl chloride in the presence of NaOH. Crude
derivatives were recrystallized from ethanol or ethanol–water as
36
white solids whose mp matched that of previously synthesized
material.
2
2,36
N-Phenylbenzamide 9a: mp 162–164 ЊC (lit.,
160 ЊC);
δH 2 7.88–7.92 (2H, m, NArH), 7.65–7.69 (2H, m, COArH),
.48–7.62 (3H, m, NArH), 7.16–7.43 (3H, m, COArH);
2,37
5 (a) W. Oppolzer and O. Tamura, Tetrahedron Lett., 1990, 31, 991;
b) W, Oppolzer, O. Tamura, G. Sundarababu and M. Signer, J. Am.
(
7
Chem. Soc., 1992, 114, 5900.
Ϫ1
νmax/cm 3345, 1655, 1599, 1531, 1439, 1250, 1070, 755, 715,
6 (a) E. Erdik and M. Ay, Synth. React. Inorg. Metal.-Org. Chem.,
1989, 19, 663; (b) E. Erdik, in Encyclopedia of Reagents for Organic
Synthesis, ed. L. A. Paquette, Wiley, New York, 1995, vol. 1, p. 41.
6
98.
N-p-Tolylbenzamide 9b: mp 158 ЊC (lit.,
22,36
22,37
158 ЊC); δH
7
8
9
H. Tsutsui, J. Hayashi and K. Narasaka, Chem. Lett., 1997, 317.
H. Mitchell and J. Leblanc, J. Org. Chem., 1994, 59, 682.
P. Beak and G. W. Selling, J. Org. Chem., 1989, 54, 5574.
7
7
.85–7.92 (2H, m, NArH), 7.52–7.58 (2H, m, COArH), 7.44–
.50 (3H, m, COArH), 7.15–7.20 (2H, m, NArH), 2.30 (s,
Ϫ1
ArCH ); νmax/cm 3308, 1647, 1599, 1531, 1404, 1265, 1024,
3
10 A. Alberti, F. Canè, P. Dembech, D. Lazzari, A. Ricci and
G. Seconi, J. Org. Chem., 1996, 61, 1677.
11 B. Carboni and M. Voultier, Bull. Soc. Chim. Fr., 1995, 132, 1003.
8
13, 697.
36
N-(p-Methoxyphenyl)benzamide 9c: mp 154–157 ЊC (lit.,
1
2 R. Hagopian, M. J. Therien and J. R. Murdoch, J. Am. Chem. Soc.,
1
54 ЊC); δH 7.85–7.90 (m, 2H, NArH), 7.78–7.82 (1H, br s,
1
984, 106, 5753.
NH), 7.52–7.60 (2H, m, COArH), 7.45–7.52 (3H, m, COArH),
Ϫ1
13 (a) G. H. Coleman, J. L. Hermanson and W. J. Johnson, J. Am.
Chem. Soc., 1937, 59, 1896; (b) G. H. Coleman, W. P. Andersen and
J. L. Hermanson, J. Am. Chem. Soc., 1934, 56, 1381.
14 C. Greck, L. Bischoff, F. Ferreira, C. Pinel, E. Piveteau and
J. P. Genêt, Synlett, 1993, 475.
6
.90–6.96 (m, 2H, NArH), 3.82 (s, OCH ); νmax/cm 3329,
3
2
850, 1647, 1519, 1412, 1250, 1032, 820, 654.
36
N-(p-Bromophenyl)benzamide 9d: mp 203 ЊC (lit., 204 ЊC);
δH 7.86–7.90 (2H, m, NArH), 7.78–7.87 (1H, br s, NH), 7.58–
.60 (2H, m, COArH), 7.48–7.55 (2H, m, COArH), 7.27–7.30
1
5 F. Canè, D. Brancaleoni, P. Dembech, A. Ricci and G. Seconi,
Synthesis, 1997, 545.
7
Ϫ1
(
2H, m, NArH); νmax/cm 3332, 1647, 1578, 1522, 1491, 1385,
1
1
1
6 R. Reike, Tetrahedron Lett., 1998, 39, 9157.
7 P. Knochel and R. Singer, Chem. Rev., 1993, 93, 2117.
8 P. Knochel, Synlett, 1995, 393.
1
250, 1070, 1005, 820, 715, 654, 508.
N-(p-Ethoxycarbonylphenyl)benzamide 9e: mp 150 ЊC (lit.,
36
1
48 ЊC); δ 7.96–8.07 (2H, m, NArH), 7.86–7.90 (2H, m, NArH),
19 E. Erdik, Organozinc Reagents in Organic Synthesis, CRC Press,
H
7
.30–7.60 (5H, m, COArH), 7.37 (2H, q, CO CH CH ), 1.39
Florida, 1996.
2
2
3
Ϫ1
2
2
0 P. Knochel, J. J. Almena and P. Jones, Tetrahedron, 1998, 54, 8275.
1 P. Beak and B. J. Kokko, J. Org. Chem., 1982, 47, 2822.
22 R. Brown and W. Jones, J. Chem. Soc., 1946, 781.
3 N. I. Scheverdina and Z. Kotscheschkov, J. Gen. Chem. USSR
(
3H, t, CO CH CH ); νmax/cm 3360, 1710, 1605, 1452, 1310,
2 2 3
1
270, 1115, 712, 687, 650.
N-Hexylbenzamide 9f: mp 40 ЊC (lit., 40 ЊC); δH 7.74–7.81
2H, m, COArH), 7.36–7.48 (3H, m, COArH), 6.30–6.60 (1H,
36
2
(
(
Engl. Transl.), 1938, 8, 1825.
br s, NH), 3.38–3.45 (2H, m, NCH ), 1.55–1.65 (2H, m,
NCH CH ), 1.25–1.40 (6H, m, NCH CH CH CH CH ), 0.85–
24 E. Erdik and T. Daskapan, Synth. Commun., 1999, 29 (in
2
¸
publication).
2
2
2
2
2
2
2
Ϫ1
2
5 M. Uchiyama, M. Kemada, O. Mishima, N. Yokoyama, M. Koike,
Y. Kondo and T. Sakamoto, J. Am. Chem. Soc., 1998, 120, 4934.
26 B. M. Trost and W. H. Pearson, J. Am. Chem. Soc., 1983, 105, 1054.
7 J. Leonard, B. Lygo and G. Procter, Advanced Practical Organic
Chemistry, Blackie, London, 1995.
0
1
.95 (3H, t, CH CH ); νmax/cm 3341, 2925, 2855, 1631, 1570,
2 3
530, 1485, 1275, 1155, 1070, 718, 687.
N-Cyclohexylbenzamide 9g: mp 149 ЊC (lit., 149 ЊC);
δH 7.74–7.78 (2H, m, COArH), 7.38–7.50 (3H, m, COArH),
3
6
2
6
2
5
1
.10–6.20 (1H, br s, NH), 3.84–4.05 (1H, br s, NCH), 1.72–
.10 (4H, m, 2-H and 6-H ), 1.28–1.50 (6H, m, 3-, 4- and
-H ); νmax/cm 3312, 2932, 2855, 1620, 1578, 1535, 1480,
28 G. B. Kaufman and L. A. Teter, Inorg. Synth., 1963, 7, 9.
29 H. J. Barber, J. Chem. Soc., 1943, 1, 79.
2
Ϫ1
3
0 R. J. K. Taylor, Organocopper Reagents. A Practical Approach,
2
Oxford University Press, Oxford, 1994.
152, 1080, 690.
36
37
31 Y. Yamamato, Y. Chounan, M. Tanaka and T. Ibuka, J. Org. Chem.,
992, 57, 1024.
N-Benzylbenzamide 9h: mp 106 ЊC (lit., 105 ЊC); δH 7.76–
1
7
.84 (2H, m, COArH), 7.40–7.55 (3H, m, COArH), 7.32–7.40
3
2 L. A. Carpino, J. Am. Chem. Soc., 1960, 82, 3133.
33 H. Hjeds, Acta Chem. Scand., 1965, 19, 1764.
34 J. C. Watson and J. F. Eastham, J. Organomet. Chem., 1967, 9, 165.
5 B. S. Furniss, A. J. Hannaford, V. Rogers, P. W. G. Smith and
A. R. Tachell, Vogel ’s Textbook of Practical Organic Chemistry,
Longman, London, 1981, p. 1129.
(
5H, m, NCH ArH), 6.50–6.52 (1H, br s, NH), 4.62–4.68 (2H,
2
Ϫ1
s, NCH ); νmax/cm 3287, 1637, 1605, 1552, 1415, 1261, 1070,
2
3
9
80, 785, 697.
3
6 Handbook of Tables for Organic Compound Identification, ed. Zvi
Rappoport, CRC Press, Inc., Florida, 1980.
Acknowledgements
13
1
We are grateful to the Turkish Scientific and Technical Research
Council (Grant No. TBAG-1618), the Ankara University
Research Fund (Grant No. 96250026) and NATO (Research
Grant No. CRG971168) for financial support.
37 The Aldrich Library of C and H NMR Spectra, ed. C. J. Pouchert
and J. Behnke, Aldrich Chem. Co., Milwaukee, 1993.
Paper 9/06093F
3
142
J. Chem. Soc., Perkin Trans. 1, 1999, 3139–3142