MERCURY(II) NITRATE
1
Mercury(II) Nitrate
1
Hg(NO
3
)
2
·H
2
O
[7783-34-8]
H
2
HgN
2
O
7
(MW 342.63)
InChI = 1/Hg.2NO3.H2O/c;2*2-1(3)4;/h;;;1H2/q+2;2*-1;
InChIKey = KVICROHOONHSRH-UHFFFAOYAE
(oxymercuration;
4
–
9
amidomercuration;
12,15
cyclopropane
cleavage;
17,19
glycosylation
23
)
Alternate Name:
mercuric nitrate.
Physical Data:
mp 79
◦
C; bp (dec); d 4.3 g cm
−
3
.
Solubility:
insol alcohol; very sol H
2
O (in dilute solutions forms
an insol basic salt); sol acetone, THF, DME, dioxane, NH
3
,
HNO
3
, and other dilute acids.
Form Supplied in:
transparent, hygroscopic crystals with slight
odor of HNO
3
.
Drying:
heating of the monohydrate to 55–60
◦
C/10
−
2
mmHg.
2,3
Handling, Storage, and Precautions:
acute poison. Exposure to
all mercury compounds is to be strictly avoided. Releases toxic
Hg fumes when heated to decomposition. Protect from light.
Oxymercuration. The reactivity of Hg(NO
3
)
2
is similar to
that of other Hg
II
salts (acetate and trifluoroacetate)
1
so that this
reagent can be employed to achieve similar goals such as elec-
trophilic additions. The nitrate is often superior to its relatives
(due to its higher electrophilicity) and may exhibit some vari-
ations in reactivity.
4
Thus, for instance, conjugated dienes af-
ford products of both 1,4- and 1,2-addition (eq 1).
5,6
By contrast,
with Hg(OAc)
2
, only the 1,2-adduct is formed.
5
In the absence of
stronger nucleophiles (in a nonnucleophilic solvent), nitratomer-
curation has been observed.
7
In the presence of Cl
2
or Br
2
, the
HgX group in the original adduct is replaced by halogen.
7
ClHg
OMe
ClHg
1. Hg(NO
3
)
2
, MeOH
OMe
(1)
+
2:1
2. KCl
In the presence of Hydrogen Peroxide, alkenes are peroxymer-
curated
8
on reaction with Hg(NO
3
)
2
as a result of H
2
O
2
being a
stronger nucleophile than NO
3
−
.
Like other Hg
II
salts, mercury(II) nitrate effects intramolecu-
lar alkoxymercuration of unsaturated alcohols to produce oxy-
gen heterocycles (eq 2).
9
Similar to other electrophilic additions,
oxymercuration is a priori a reversible reaction. It has been shown
that selecting the method of quenching is crucial to minimize the
reversion. Thus, oxymercuration products with rigid, antiperipla-
nar arrangement of the C–HgX and C–O bonds (eq 2) imme-
diately revert back to the starting material upon treatment with
sources of hard halogen anion (NaCl, KBr, CuCl
2
, etc.). By con-
trast, quenching with soft reagents (e.g. CuCl) reliably affords the
stable chloromercurio compound. Excess of strong acids should
be avoided as H
+
catalyzes reversion.
9,10
HO
AcO
AcO
HgCl
O
O
HgNO
3
AcO
(2)
Hg(NO
3
)
2
CuCl
NaCl
In a close analogy to alkenic alcohols, unsaturated hydroperox-
ides react with Hg(NO
3
)
2
to give cyclic peroxides which can be
further elaborated.
8,11
Amidomercuration.
12
The mercuration of terminal or cyclic
alkenes with Hg(NO
3
)
2
in MeCN
12,13,14
affords amides via the
Ritter reaction (eq 3).
13
In contrast to the original, strong acid-
mediated reaction, this modification is less prone to rearrange-
ments as it proceeds via a mercuronium ion.
13,14
The reaction
works with mono- and disubstituted double bonds but fails with
trisubstituted alkenes.
14
Other Hg
II
salts, namely (AcO)
2
Hg and
(CF
3
CO
2
)
2
Hg, are not satisfactory,
13
apparently owing to their
lower electrophilicity.
1. Hg(NO
3
)
2
R
HN
R
COMe
+
(3)
MeCN
2. NaBH
4
Primary amides and TsNH
2
similarly add across alkenic double
bonds to give the corresponding tosylamides.
15
Asymmetric, in-
tramolecular amidomercuration employing chiral carbamates has
also been described (eq 4).
16
R*O
N
H
O
O
CCl
3
O
N
R*O
O
CCl
3
HgX
(4)
*
*
*
1 h
Hg(NO
3
)
2
MeCN
Cyclopropane Ring Opening.
17
–
19
Mercury(II) nitrate ap-
pears to be the reagent of choice to accomplish stereospecific cor-
ner opening
19
of cyclopropyl derivatives (eqs 5 and 6);
19,20
other
Hg
II
salts are less reactive.
19,21
The reaction is also regioselective:
the cleavage occurs between the most and the least substituted
carbon.
19
The resulting organomercurials can be transmetalated
by transition metals (Pd, Mo, Cu) to accomplish a variety of in-
teresting transformations.
19
(5)
OH
BrHg
1. Hg(NO
3
)
2
O
Hg
2+
2. KBr
Avoid Skin Contact with All Reagents
2
MERCURY(II) NITRATE
(6)
O
O
1. Hg(NO
3
)
2
BrHg
Hg
2+
2. KBr
Glycosylation.
Thioglycosides can be utilized as glyco-
sylating agents in conjunction with anhydrous Hg(NO
3
)
2
(or
AgNO
3
).
22
Although the reaction normally affords mixtures of
α
- and β-glycosides,
22
neighboring group participation can render
it stereoselective (for discussion and examples, see Mercury(II)
Chloride–Cadmium Carbonate).
23
Miscellaneous. β-Pinene undergoes a Ritter-type transforma-
tion on reaction with Hg(NO
3
)
2
/MeCN
24
to give the starting ma-
terial for the synthesis of aristoteline
25
and other indole alkaloids
(eq 7);
25
the reaction is not enantioselective and gives racemic
products.
24,25
Mercuration of enolizable ketones has little syn-
thetic value: thus, for instance, acetone has been found to produce
a mixture of nine compounds.
26
(7)
O
N
Hg(NO
3
)
2
MeCN
Related Reagents. Mercury(II) Acetate; Mercury(II) Trifluo-
roacetate; Mercury(II) Perchlorate.
1.
(a) Larock, R. C., Angew. Chem., Int. Ed. Engl. 1978, 17, 27. (b) Larock,
R. C., Tetrahedron 1982, 38, 1713. (c) Larock, R. C. Organomercury
Compounds in Organic Synthesis
; Springer: Berlin, 1985. (d) Larock,
R. C. Solvomercuration/Demercuration Reactions in Organic Synthesis;
Springer: Berlin, 1986.
2.
Sokolov, V. I.; Reutov, O. A., Izv. Akad. Nauk SSSR, Ser. Khim. 1968,
225.
3.
Fieser & Fieser 1982
, 10, 254.
4.
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, 26, 1800.
5.
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6.
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7.
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Lett. 1990
, 31, 5513.
9.
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10.
For further discussion, see: Lilikarntakul, S.; Hirama, M.; Itô, S.,
Tetrahedron Lett. 1987
, 28, 1207.
11.
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Commun. 1989
, 954.
12.
(a) Fry, A. J.; Simon, J. A., J. Org. Chem. 1982, 47, 5032. (b) Barluenga,
J.; Jimenez, C.; Najera, C.; Yus, M., J. Chem. Soc., Perkin Trans. 1 1983,
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831.
13.
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14.
(a) Chow, D.; Robson, J. H.; Wright, G. F., Can. J. Chem. 1965, 43, 312.
(b) Geger, J.; Vogel, D., J. Prakt. Chem. 1969, 311, 737. (c) Kozikowski,
A. P.; Scripko, J., Tetrahedron Lett. 1983, 24, 2051. (d) Henning, R.;
Urbach, H., Tetrahedron Lett. 1983, 24, 5343.
15.
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Commun. 1981
, 670 and 1178.
16.
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1989, 30, 4775.
17.
(a) Collum, D. B.; Mohamadi, F.; Hallock, J. S., J. Am. Chem. Soc. 1983,
105
, 6882. (b) Collum, D. B.; Still, W. C.; Mohamadi, F., J. Am. Chem.
Soc. 1986
, 108, 2094.
18.
(a) Bandaev, S. G.; Eshnazarov, Yu. Kh.; Nasyrov, I. M.; Mochalov, S.
S.; Shabarov, Yu. S., Zh. Org. Khim. 1988, 24, 733. (b) Bandaev, S. G.;
Eshnazarov, Yu. Kh.; Mochalov, S. S.; Shabarov, Yu. S.; Zefirov, N. S.,
Metalloorg. Khim. 1992
, 5, 690 (Chem. Abstr. 1992, 117, 251 458j).
19.
(a) Koˇcovský, P.; Šrogl, J., J. Org. Chem. 1992, 57, 4565. (b) Koˇcovský,
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33
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Org. Chem. 1995
, 60, 482.
20.
Langbein, G.; Siemann, H.-J.; Gruner, I.; Müller, C., Tetrahedron 1986,
42
, 937.
21.
Similar reactivity has been observed for isoelectronic Tl
III
: Koˇcovsky,
P.; Pour, M.; Gogoll, A.; Hanuš, V.; Smrˇcina, M., J. Am. Chem. Soc.
1990, 112, 6735.
22.
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24.
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94
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25.
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26.
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Pavel Koˇcovský
University of Leicester, Leicester, UK
A list of General Abbreviations appears on the front Endpapers