Categories: C-C Bond Formation > Chains >
Allylic Substitutions, Allylation
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Name Reactions
Recent Literature
Nickel-Catalyzed Asymmetric Negishi Cross-Couplings of Secondary Allylic
Chlorides with Alkylzincs
S. Son, G. C. Fu, J. Am. Chem. Soc., 2008,
130, 2756-2757.
The reaction of secondary and tertiary alkyl halides with benzylic or allylic
Grignard reagents in the presence of a catalytic amount of silver nitrate in
ether yielded the corresponding cross-coupling products in high yields. The
coupling reaction provides efficient access to quaternary carbon centers.
H. Someya, H. Ohmiya, H. Yorimitsu, K. Oshima, Org. Lett., 2008,
10, 969-971.
Efficient enantioselective Cu-catalyzed alkylations of aromatic and
aliphatic allylic phosphates bearing di- and trisubstituted olefins are
promoted in the presence of a readily available chiral amino acid-based
ligand. Tertiary and quaternary stereogenic carbon centers are delivered
regioselectively in high ee.
M. A. Kacprzynski, A. H. Hoveyda, J. Am. Chem. Soc.,
2004,
126, 10676-10681.
Direct Csp3−Csp3 coupling of various aliphatic
trimethylsilyl ethers and allylsilanes is effectively catalyzed by InCl3
and I2. The transformation probably involves an in situ-derived
combined Lewis acid of InCl3 and Me3SiI. The reaction
allows the construction of quaternary-quaternary and quaternary-tertiary
carbon-carbon bonds and tolerates aryl halide moieties.
T. Saito, Y. Nishimoto, M. Yasuda, A. Baba, J. Org. Chem., 2007,
72, 8588-8590.
A promising new approach to a generalized allylation process uses various
easily accessible allyl diphenylphosphine oxides as radical trapping agents
for the allylation of ditihocarbonates.
G. Ouvry, B. Quiclet-Sire, S. Z. Zard, Angew. Chem. Int. Ed., 2006,
45, 5002-5006.
The palladium-catalyzed reaction of allyl acetates with aryl- and
vinyltin reagents gave good yields of cross-coupled products. The reaction
was mild and tolerant of functionality (-CO2R, -OH, -OSiR3,
-OMe) in the tin reagent. Inversion of stereochemistry at the acetate center
was observed, with retention of the geometry of the olefin of the allyl
group and with exclusive coupling at the primary position. Retention of
geometry of the olefin in the vinyltin reagents was also observed.
L. Del Valle, J. K. Stille, L. S. Hegedus, J. Org. Chem, 1990,
55, 3019-3023.
In a Pd-catalyzed cross-coupling of aromatic and aliphatic allylic carbonates
and allylB(pin), small-bite-angle ligands favor the branched substitution
product. This mode of regioselection is consistent with a reaction that operates
by a 3,3′ reductive elimination reaction. In the presence of appropriate chiral
ligands, this reaction is rendered enantioselective.
P. Zhang, L. A. Brozek, J. P. Morken, J. Am. Chem. Soc., 2010,
132, 10686-10688.
Allylsilylation allows to install both silyl and allyl groups onto a
carbon-carbon double bond directly. Proton-exchanged montmorillonite showed
excellent catalytic performances for the allylsilylation of alkenes. Isolation
of the reaction intermediate on the montmorillonite surface helped to
investigate the reaction mechanism.
K. Motokura, S. Matsunaga, A. Miyaji, Y. Sakamoto, T. Baba, Org. Lett., 2010,
12, 1508-1511.
Enantioselective copper-catalyzed allylic alkylations of Grignard reagents were
performed on allylic bromides with a protected hydroxyl or amine functional
group using Taniaphos as a ligand. The terminal olefin moiety in the products
can be transformed into various functional groups without racemization.
A. W. van Zijl, F. López, A. J. Minnaard, B. L. Feringa, J. Org. Chem., 2007,
72, 2558-2563.
A chemo- and regioselective, Cu-catalyzed asymmetric addition of Grignard
reagents to 3-bromopropenyl esters provides allylic esters in high yields
and enantioselectivities using Taniaphos as ligand. The method is a
practical route to chiral, nonracemic allylic alcohols.
K. Geurts, S. P. Fletcher, B. L. Feringa, J. Am. Chem. Soc., 2006,
128, 15572-15573.
Chelated amino acid ester enolates are excellent nucleophiles for allylic
alkylations. With these enolates, even terminal π-allyl palladium complexes react
without significant isomerization.
K. Krämer, U. Kazmaier, J. Org. Chem., 2006,
71, 8950-8953.
Efficient Addition of Allylsilanes to α,β-Enones Using Catalytic Indium and
Trimethylsilyl Chloride
P. H. Lee, D. Seomoon, S. Kim, K. Nagaiah, S. V. Damle, K. Lee, Synthesis,
2003, 2023-2026.
The use of unsaturated methylidene ketones in catalytic conjugate allylations
allows a significant expansion in substrate scope and occurs in a highly
enantioselective fashion in the presence of a Taddol-derived phosphinite ligand.
L. A. Brozek, J. D. Sieber, J. P. Morken, Org. Lett., 2011,
13, 995-997.
The reaction of alkoxides with boron trichloride results in the generation
of cations that can be allylated in subsequent transformations. The absence
of Brønsted acids can make a significant difference in such syntheses.
G. W. Kabalka, M.-L. Yao, S. Borella, J. Am. Chem. Soc., 2006,
128, 11320-11321.
G. W. Kabalka, M.-L. Yao, S. Borella, J. Am. Chem. Soc., 2006,
128, 11320-11321.
Various acetals or alcohols react with allyl(trimethyl)silane or
1-phenyl-2-(trimethylsilyl)acetylene in the presence of a catalytic amount of
the Brønsted acid o-benzenedisulfonimide under mild conditions to give
good yields of the allylated products. The catalyst can be easily recovered and
purified for use in further reactions.
M. Barbero, S. Bazzi, S. Cadamuro, S. Dughera, C. Piccinini, Synthesis, 2010,
315-319.
α-Halonitriles react with alkyllithium, organomagnesium, and lithium
dimethylcuprate reagents generating reactive, metalated nitriles. The rapid
halogen-metal exchange with alkyllithium and Grignard reagents allows
Barbier-type reactions with various electrophiles.
F. F. Fleming, Z. Zhang, W. Liu, P. Knochel, J. Org. Chem., 2005,
70, 2200-2005.
Allyl nitroacetates undergo decarboxylative allylation to provide tertiary
nitroalkanes in high yield within several minutes under ambient conditions. The
preparation of substrate allyl nitroacetates by tandem Knoevenagel/Diels-Alder
sequences allows the facile synthesis of relatively complex substrates that
undergo diastereoselective decarboxylative allylation.
A. J. Grenning, J.A. Tunge, Org. Lett., 2010,
12, 740-742.
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Enantioselective Allylic Carbon-Carbon Bond Construction |
