Categories: C-C Bond Formation > Arenes >
Allylic Substitution, Allylation
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Aromatic Claisen Rearrangement
Recent Literature
The cross-coupling reaction of aryl and vinyl boronic acids and allylic
alcohols proceeded smoothly in toluene or dioxane in the presence of a
(triphenyl phosphite)palladium catalyst to give the corresponding
allylbenzene derivatives and 1,4-dienes. Neither cocatalysts for promoting
C-O bond cleavage of allylic alcohols nor bases for activation of
organoboron reagents are required.
Y. Kayaki, T. Koda, T. Ikariya, Eur. J. Org. Chem., 2004,
4989-4993.
Palladium-catalyzed allyl cross-coupling reaction of allylic acetates with
various boronic acids gave allyl arene derivatives in good yields at room
temperature in the presence of a catalytic amount of Pd(OAc)2 with
phosphine-free hydrazone as ligand.
T. Mino, K. Kajiwara, Y. Shirae, M. Sakamoto, T. Fujita, Synlett, 2008,
2711-2715.
A cross-coupling reaction between aryl- and vinylboronic acids and various
allylic bromides proceeded without the use of a transition-metal catalyst to
give the corresponding allylated products in good yields. The use of an
inorganic base and a small amount of water is crucial in obtaining good
performance in the present transition-metal-free reaction.
M. Ueda, K. Nishimura, R. Kashima, I. Ryu, Synlett, 2012,
1085-1089.
The Pd(0)-catalyzed allylic cross-coupling of homoallylic tosylate substrates
using boronic acids and pinacol esters uses 2-(4,5-dihydro-2-oxazolyl)quinoline
(quinox) as a ligand and is performed at ambient temperature. The scope of the
reaction is broad in terms of both the boronate and the tosylate, that includes
secondary tosylates.
B. J. Stokes, S. M. Opra, M. S. Sigman, J. Am. Chem. Soc., 2012,
134, 11408-11411.
A copper-catalyzed SN2'-selective arylation of various allylic
chlorides with arylboronic esters in the presence of a wide range of functional
groups leads to branched products in high yield. A mechanism is proposed on the
basis of the results of stoichiometric experiments and the isolation of the
proposed intermediate.
A. M. Whittaker, R. P. Rucker, G. Lalic, Org. Lett., 2010,
12, 3216-3218.
Allyl-aryl coupling between allylic acetates and arylboronic acids took place
in the presence of catalytic amounts of Pd(OAc)2,
1,10-phenanthroline, and AgSbF6 with high γ-selectivity and E:Z-selectivity.
The reaction of an optically active allylic acetate with an α-stereogenic center
proceeded with excellent α-to-γ chirality transfer.
H. Ohmiya, Y. Makida, T. Tanaka, M. Sawamura, J. Am. Chem. Soc., 2008,
130, 17276-17277.
In situ generated palladium(0) nanoparticles catalyze an efficient
cross-coupling of allyl acetates with aryl and vinyl siloxanes. The reactions
are stereoselective, and linear (E)-coupling products are obtained both
from cis and trans allyl acetates. The coupling with vinyl
siloxanes provides a novel protocol for the synthesis of 1,4-pentadienes.
R. Dey, K. Chattopadhyay, B. C. Ranu, J. Org. Chem., 2008,
73, 9461-9464.
A room-temperature Ni-catalyzed reductive coupling of aryl bromides with
secondary alkyl bromides provides products in good to excellent yields. Slight
modification of this protocol allows efficient coupling of activated aryl
chlorides with cyclohexyl bromide and aryl bromides with allylic acetate.
S. Wang, Q. Qian, H. Gong, Org. Lett., 2012,
14, 3352-3355.
An efficient Hiyama coupling reaction between benzylic halides and
aryltrialkoxysilanes using Pd nanoparticles allows the synthesis of a diverse
range of diarylmethanes which are ubiquitous units of natural products and
pharmaceuticals.
D. Srimani, A. Bej, A. Sarkar, J. Org. Chem., 2010,
75, 4296-4299.
Coupling of sterically hindered aryl and activated alkyl chlorides bearing
β-hydrogens has been successfully achieved by using N-heterocyclic
carbene (NHC)Pd-carboxylate complexes as catalysts.
R. Singh, M. S. Viciu, N. Kramareva, O. Navarro, S. P. Nolan, Org. Lett.,
2005,
7, 1829-1832.
A γ-selective, palladium-catalyzed cross-coupling of sodium
(Z)-2-butenyldiethylsilanolate provides high yields and site selectivity
with electron-rich, electron-poor, sterically hindered, and
heteroaromatic bromides. The use of a configurationally homogeneous (Z)-silanolate,
nontransferable ethyl groups, and a sterically bulky trialkylphosphonium
tetrafluoroborate salt are critical to the success of the method.
S. E. Denmark, N. S. Werner, Org. Lett., 2011,
13, 4596-4599.
Functionalized diarylzinc reagents react readily with allylic chlorides or
phosphates in the presence of Co(acac)2 as catalyst to give the SN2
products in high yields and with retention of the double-bond configuration.
Functionalities such as ester, ketone, or cyano are tolerated.
G. Dunet, P. Knochel, Synlett, 2007,
1383-1386.
The use of Zn powder in the presence of LiCl in THF allows a simple,
high-yielding preparation of a broad range of functionalized aryl- and
heteroarylzinc reagents. The synthesis of alkylzinc reagents was performed
from inexpensive alkyl bromides.
A. Krasovski, V. Malakhov, A. Gavryushin, P. Knochel, Angew. Chem. Int. Ed., 2006,
45, 6040-6044.
Generation of a π-allyl Pd species directly from a 1,3-diene via a Pd-catalyzed
aerobic alcohol oxidation enables a palladium-catalyzed reductive cross-coupling
of 1,3-dienes with boronic esters. Both the scope of the process and the origin
of a highly selective 1,2-addition are discussed.
L. Liao, M. S. Sigman, J. Am. Chem. Soc., 2010,
132, 10209-10211.
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.
Palladium-catalyzed coupling reactions of functionalized allylboronic acids
with various iodobenzenes under standard Suzuki-Miyaura coupling conditions
afforded selectively the branched allylic products in high to excellent
yields.
S. Sebelius, V. J. Olsson, O. A. Wallner, K J. Szabó, J. Am. Chem. Soc.,
2006,
128, 8150-8151.
S. Sebelius, V. J. Olsson, O. A. Wallner, K J. Szabó, J. Am. Chem. Soc.,
2006,
128, 8150-8151.
Sodium allyldimethylsilanolates and 2-butenyldimethylsilanolates undergo
cross-coupling with a wide variety of aryl bromides to afford allylated and
crotylated arenes. Reactions of allyldimethylsilanolate take place in DME
with allylpalladium chloride dimer whereas 2-butenyldimethylsilanolate delivered
branched products in toluene in the presence of Pd(dba)2 and
norbornadiene as ligand.
S. E. Denmark, N. S. Werner, J. Am. Chem. Soc., 2008,
130, 16382-16393.
S. E. Denmark, N. S. Werner, J. Am. Chem. Soc., 2008,
130, 16382-16393.
Silylated cyanohydrins of iodo-substituted aryl, heteroaryl, or cycloalkenyl
ketones undergo an I/Mg-exchange using i-PrMgCl·LiCl. After
subsequent reactions with electrophiles, a facile deprotection
produces polyfunctional ketones in good overall yiels. An extension to
aromatic iodoaldehydes is described.
C.-Y. Liu, H. Ren, P. Knochel, Org. Lett.,
2006,
8, 617-629.
Treatment of fluorapatite with an aqueous solution of RhCl3 resulted
in rhodium-exchanged fluorapatite catalyst (RhFAP), which successfully promoted
cross coupling of Baylis-Hillman adducts with a variety of arylboronic
acids to yield trisubstituted olefins in a highly stereoselective manner. RhFAP
was recovered quantitatively by simple filtration and reused with almost
consistent activity.
M. L. Kantam, K. B. S. Kumar, B. Sreedhar, J. Org. Chem., 2008,
73, 320-322.
A palladium-catalyzed cross-coupling reaction between acetates of
Baylis-Hillman adducts and organosilanes in PEG as solvent is described.
G. W. Kabalka, J. Org. Chem., 2005,
70, 9207-9210.
A highly enantioselective Rh-catalyzed asymmetric allylic substitution allows
the desymmetrization of meso cyclopent-2-ene-1,4-diethyl dicarbonates.
Depending on the ligand, each of two regioisomeric products can be obtained in
good yield and excellent enantioselectivity. Whereas bisphosphine P-Phos ligands
form trans-1,2-arylcyclopentenols, Segphos ligands lead predominantly to
trans-1,4-arylcyclopentenols.
F. Menard, D. Perez, D. S. Roman, T. M. Chapman, M. Lautens, J. Org. Chem., 2010,
75, 4056-4068.
G. W. Kabalka, J. Org. Chem., 2005,
70, 9207-9210.
