Zinc
Name Reactions
Recent Literature
In the presence of Co(PPh3)2I2, PPh3,
water, and zinc powder, the reductive coupling of alkynes with alkenes
having an electron-withdrawing substituent proceeded smoothly in
acetonitrile to give the corresponding reductive coupling products in fair
to excellent yields. Possible mechanisms for this highly regio- and
stereoselective ene-yne reaction are proposed.
C.-C. Wang, P.-S. Lin, C.-H. Cheng, J. Am. Chem. Soc., 2002, 124, 9696-9697.
A nonionic amphiphile enables a simple approach to Pd-catalyzed stereoselective sp3-sp2
cross-couplings between alkyl and alkenyl bromides in the presence of zinc
powder in water to give coupled products in good yields without prior formation
of the organozinc reagents. The reaction is conducted at room temperature and
tolerates various functional groups.
A. Krasovskiy, C. Duplais, B. H. Lipshutz, Org. Lett., 2010,
12, 4742-4744.
Zn-Mediated, Pd-Catalyzed Cross-Couplings in Water at Room Temperature
Without Prior Formation of Organozinc Reagents
A. Krasovskiy, C. Duplais, B. H. Lipshutz, J. Am. Chem. Soc., 2009,
131, 15592-15593.
The efficient olefination from organozinc reagents with aldehydes is
exploited in a new synthesis of aryl and alkyl olefins.
J.-X. Wang, Y. Fu, Y. Hu, K. Wang, Synthesis, 2003, 1506-1510.
A Mannich-like zinc-mediated three-component reaction of aromatic halides,
amines, and paraformaldehyde allows the straightforward synthesis of a range of
functionalized tertiary benzylamines. This procedure involves the in situ
formation of arylzinc reagents.
E. Le Gall, A. Decompte, T. Martens, M. Troupel, Synthesis, 2010,
249-254.
A straightforward three-component reaction of preformed aromatic or in situ
generated benzylic organozinc reagents with amines and ethyl glyoxylate allows
the synthesis of a range of α-amino esters in very good yields. The procedure,
which is characterized by its simplicity, allows the concise synthesis of esters
bearing a phenylglycine or a phenylalanine scaffold.
C. Haurena, E. Le Gall, S. Sengmany, T. Martens, M. Troupel, J. Org. Chem., 2010,
75, 2645-2650.
In acetonitrile as solvent and in the presence of a simple cobalt halide as
catalyst, the reduction by zinc dust of a mixture of aldehydes or ketones
and allylic acetates affords the corresponding homoallylic alcohols in good
yields.
P. Gomes, C. Gosmini, J. Périchon, Synthesis, 2003, 1909-1915.
A rapid and efficient procedure for the solvent-free synthesis of
homoallylic and homopropargyl alcohols has been achieved by zinc-mediated
Barbier-type reaction of carbonyl compounds at room temperature.
J.-X. Wang, X. Jia, T. Meng, L. Xin, Synthesis, 2005, 2669-2672.
J.-X. Wang, X. Jia, T. Meng, L. Xin, Synthesis, 2005, 2669-2672.
Titanocene dichloride catalyzes the formation of an organozinc species via
catalytic activation of allyl halides. Nucleophilic addition to carbonyl
derivatives provides the desired homoallylic alcohols in very good yields in
short reaction times. This discovery will have wide ranging applicability in the
generation of highly reactive organometallic reagents.
L. M. Fleury, B. L. Ashfeld, Org. Lett., 2009,
11, 5670-5673.
Zinc-promoted reduction of 2-(bromomethyl)alkenoates derived from
Baylis–Hillman adducts gave (E)-2-methylacrylates in good yield and
high stereoselectivity. Synthesis of the male ant pheromone (E)-2,4-dimethyl-2-hexenoic
acid was performed using this simple methodology.
L. Fernandes, A. J. Bortoluzzi, M. M. Sa, Tetrahedron, 2004, 60, 9983-9989.
An efficient cobalt-catalyzed reductive coupling reaction of alkyl halides
with alkenes bearing electron-withdrawing groups in the presence of water
and zinc powder in acetonitrile gave the corresponding Michael-type addition
products in high yields. The mechanism is discussed.
P. Shukla, Y.-C. Hsu, C.-H. Cheng, J. Org. Chem., 2006, 71, 655-658.
Cobalt complex/Zn systems effectively catalyze the reductive coupling of
activated alkenes with alkynes in the presence of water to give substituted
alkenes with very high regio- and stereoselectivity in excellent yields.
H.-T. Chang, T. T. Jayanth, C.-C. Wang, C.-H. Cheng, J. Am. Chem. Soc.,
2007,
129, 12032-12041.
A range of polysubstituted allylic zinc chlorides were obtained in good yield
using a LiCl-mediated zinc dust insertion in polysubstituted allylic chlorides.
A highly diastereoselective synthesis of homoallylic alcohols bearing up to two
adjacent quaternary centers by the addition of polysubstituted allylic zinc
reagents to carbonyl compounds.
H. Ren, G. Dunet, P. Mayer, P. Knochel, J. Am. Chem. Soc., 2007,
129, 5376-5377.
A dizinc reagent, which acts as an effective bidentate Lewis acid, is easily
prepared from diiodomethane and zinc powder.
K. Nomura, K. Oshima, S. Matsubara, Angew. Chem. Int. Ed., 2005,
44, 5860-5863.
Efficient, simple, cheap, and environmentally benign preparations of
cyclopropanes were achieved. One method is based on a 3-exo-trig cyclisation of
various electron-deficient 2-iodoethyl-substituted olefins with zinc powder in a
mixture of t-butyl alcohol and water, and the other on a 3-exo-tet
cyclisation of various 1,3-dihalopropanes with zinc powder in ethanol.
D. Sakuma, H. Togo, Tetrahedron, 2005,
61, 10138-10145.
D. Sakuma, H. Togo, Tetrahedron, 2005,
61, 10138-10145.
The CoI2(dppe)-catalyzed diastereoselective reductive [3 + 2]
cycloaddition of allenes and enones gives cyclopentanols in very good yields in
the presence of zinc, zinc iodide, and water.
H.-T. Chang, T. T. Jayanth, C.-H. Cheng, J. Am. Chem. Soc., 2007,
129, 4166-4167.
A zinc/indium chloride-mediated pinacol cross-coupling reaction between aldehyde
and α,β-unsaturated ketone in aqueous media gives 1,2-diols in good yields with
up to 93:7 diastereoselectivity.
Y.-S. Yang, Z.-L. Shen, T.-P. Loh, Org. Lett., 2009,
11, 2213-2215.
A mild and convenient free-radical cyclization of organohalides in the presence
of a NiCl2 • DME/Pybox complex as the catalyst and zinc powder in
methanol efficiently gives carbo-, oxa-, and azacycles as products in high
yields from unsaturated alkyl halides.
H. Kim, C. Lee, Org. Lett., 2011,
13, 2050-2053.
CuI-nanoparticles catalyze a selective synthesis of phenols, anilines, and
thiophenols from aryl halides in the absence of both ligands and organic
solvents. Anilines were formed selectively with ammonia competing with
hydroxylation and thiophenols were generated selectively with sulfur powder
after subsequent reduction competing with hydroxylation and amination.
H.-J. Xu, Y.-F. Liang, Z.-Y. Cai, H.-X. Qi, C.-Y. Yang, Y.-S. Feng, J. Org. Chem., 2011,
76, 2296-2300.
An efficient one-pot procedure for the zinc-mediated reduction of nitroarenes
in the presence of chloroformates leads to the corresponding N,O-bisprotected
hydroxylamines in good yield under ambient conditions in THF-water mixtures.
Solvolysis of the bisprotected hydroxylamines with sodium methoxide at room
temperature provides access to synthetically versatile N-aryl-N-hydroxy
carbamates in excellent yields.
A. Porzelle, M. D. Woodrow, N. C. O. Tomkinson, Synlett, 2009,
798-802.
Upon treatment with aqueous sodium hydroxide in DMF, a range of chalcones
underwent Michael addition reactions with nitroalkanes. The resulting
adducts were reduced in situ with Zn/HCl (aq) to afford substituted Δ1-pyrrolines
in high yields after a cyclization.
Y. Liang, D. Dong, Y. Lu, Y. Wang, W. Pan, Y. Chai, Q. Liu, Synthesis, 2006, 3301-3304.
A convenient and highly regioselective method allows the synthesis of
5-methylenepyrrolidinone derivatives from various nitriles and acrylamides via a
cobalt-catalyzed reductive coupling reaction. A possible mechanism involves the
formation of a cobaltaazacyclopentene intermediate from nitrile and acrylamide,
protonation, keto-amide cyclization, and dehydration.
Y.-C. Wong, K. Parthsarathy, C.-H. Cheng, J. Am. Chem. Soc., 2009,
131, 18252-18253.
An efficient and convenient nickel-catalyzed cyclization of 2-iodoanilines
with alkynyl aryl ketones gives 2,4-disubstituted quinolines. Naturally
occurring quinoline derivatives have been prepared in good yields. The
mechanism is discussed.
R. P. Korivi, C.-H. Cheng, J. Org. Chem., 2006, 71, 7079-7082.
The highly active mixed-ligand catalytic system NiCl2(dppp)/dppf
combined with the reducing effect of zerovalent Zn enables a dramatic
acceleration of the rate of the neopentylglycolborylation of aryl halides. A
diversity of electron-rich and electron-deficient aryl iodides, bromides, and
chlorides were efficiently neopentylglycolborylated in very good yields,
typically in 1 h or less.
P. Leowanawat, A.-M. Resmerita, C. Moldoveanu, C. Liu, N. Zhang, D. A. Wilson,
L. M. Hoang, B. M. Rosen, V. Persec, J. Org. Chem., 2010,
75, 7822-7828.
The mixed-ligand system NiCl2(dppp)/dppf is an effective catalyst for
the neopentylglycolborylation of ortho-, meta-, and para-substituted
electron-rich and electron-deficient aryl mesylates and tosylates. The addition
of Zn powder as a reductant dramatically increases the reaction yield and
reduces the reaction time, providing complete conversion in 1-3 h.
D. A. Wilson, C. J. Wilson, C. Moldoveanu, A.-M. Resmerita, P. Corcoran, L. M.
Hoang, B. M. Rosen, V. Percec, J. Am. Chem. Soc., 2010,
132, 1800-1801.
