A highly regio- and enantioselective rhodium-catalyzed allylic alkylation of 1,3-diketones with racemic secondary allylic alcohols provides chiral branched α-allylated 1,3-diketones in very good yields. Both aryl- and aliphatic-substituted allyl alcohols are suitable substrates. This reaction offers mild conditions, broad substrate scope, and readily available substrates.
S.-B. Tang, X. Zhang, H.-F. Tu, S.-L. You, J. Am. Chem. Soc., 2018, 140, 7737-7742.
A combination of tetrakis(triphenylphosphine)palladium and a carboxylic acid such as 1-adamantanecarboxylic acid allows the allylic substitution of allyl alcohols in an aqueous suspension. Various substrates are applicable to this catalytic system.
K. Manabe, S. Kobayashi, Org. Lett., 2003, 5, 3241-3244.
A Rh(I)/DPEphos/p-CF3-benzoic acid as the catalyst system achieves a highly regioselective C-C bond formation using terminal alkynes and 1,3-dicarbonyl compounds to provide valuable branched α-allylated 1,3-dicarbonyl products in very good yields. A broad range of functional groups were tolerated.
T. M. Beck, B. Breit, Org. Lett., 2016, 18, 124-127.
A salt-free, regioselective Fe-catalyzed allylic alkylation of allyl carbonates with active methylene compounds gave coupled products in good to excellent yields. Addition of triphenylphosphane led to a significant increase of the reactivity of the stable Fe(II) complex.
B. Plietker, Angew. Chem. Int. Ed., 2006, 45, 1469-1473.
The reaction of 1,3-diketones, ketoesters, and ketoamides under non-anhydrous conditions with substituted 1-phenylethanols gave benzylated products in high yields in the presence of rare earth metal and hafnium triflates as catalysts. The allylation of a diketone with allylic alcohols was also possible. Catalysts can be recovered by water extraction and reused up to five times.
M. Noji, Y. Konno, K. Ishii, J. Org. Chem., 2007, 72, 5161-5167.
Perchloric acid-catalyzed additions of various β-dicarbonyl compounds to a series of secondary alcohols and alkenes could be conveniently conducted in commercial solvent and gave good yields. Moreover, silica gel-supported HClO4 could also catalyze the heterogeneous addition for a series of substrates with similar or even higher yields. The supported catalyst could be readily recovered and reused for four runs.
P. N. Liu, L. Dang, Q. W. Wang, S. L. Zhao, F. Xia, Y. J. Ren, X. Q. Gong, J. Q. Chen, J. Org. Chem., 2010, 75, 5019-5020.
Carreira's chiral Ir/(P, olefin) complex enables an enantioselective allylic alkylation of branched racemic allylic alcohols with malonates with excellent enantioselectivity. The malonates could be used directly as efficient nucleophiles without the need for preactivation.
C.-Y. Meng, X. Liang, K. Wei, Y.-R. Yang, Org. Lett., 2019, 21, 840-843.
A cobalt-catalyzed enantioselective allylic alkylation of malononitriles with allylic carbonates provides chiral γ,δ-unsaturated malononitriles with >20:1 branched/linear regioselectivity and up to 99% enantiomeric excess under mild reaction conditions. The ligand is essential to realize the high reactivity in the carbon-carbon bond formation process.
S. Ghorai, S. U. Rehman, W.-B. Xu, W.-Y. Huang, C. Li, Org. Lett., 2020, 22, 3519-3523.
A one-pot procedure for the synthesis of 2-alkyl-2-arylcyanoacetates based on a Pd(OAc)2/dppf-catalyzed enolate arylation followed by in situ alkylation tolerates a diverse range of aryl and heteroaryl bromides, and provides a rapid entry to a wide range of products in very good to yield.
X. Wang, A. Guram, E. Bunel, G.-Q. Cao, J. R. Allen, M. M. Faul, J. Org. Chem., 2008, 73, 1643-1645.
The reaction of allenes with active methylenes proceeded smoothly in the presence of Pd(PPh3)4/PhCOOH to give the corresponding monoallylated products with E-stereoselectivity in good yields.
N. T. Patil, N. K. Pahadi, Y. Yamamoto, Synthesis, 2004, 2186-2190.
A mild and direct indium-catalyzed process for the C-C bond formation from alcohols and active methylenes, alkoxyketones or indoles was developed.
M. Yasuda, T. Somyo, A. Baba, Angew. Chem. Int. Ed., 2006, 45, 793-794.
A synergistic chiral primary amine/achiral palladium catalyzed enantioselective terminal addition to allenes with α-branched β-ketocarbonyls and aldehydes affords allylic adducts bearing acyclic all-carbon quaternary centers with high regio- and enantioselectivity. A wide range of allenes can be employed.
H. Zhou, Y. Wang, L. Zhang, M. Cai, S. Luo, J. Am. Chem. Soc., 2017, 139, 3631-3634.
An allylic alkylation/ring-closing metathesis domino process is catalyzed by the combination of a palladium and a ruthenium catalyst. This study demonstrates the compatibility of the two catalytic systems. Evidence for Grubbs' catalysts activity in allylic alkylation is also reported.
C. Kammerer, G. Prestat, T. Gaillard, D. Madec, G. Poli, Org. Lett., 2008, 10, 405-408.
A highly enantioselective catalytic alkylation of cyanoacetates was achieved using a chiral phase-transfer catalyst to give α,α-disubstituted α-cyanoacetates which have a chiral quaternary carbon.
K. Nagata, D. Sano, T. Itoh, Synlett, 2007, 547-550.
The use of a H8-BINOL-based phosphoramidite ligand enables a Pd-catalyzed highly enantioselective three-component coupling of 1,3-dienes with aryl iodines and sodium dialkyl malonates via a Pd-catalyzed cascade arylation and asymmetric allylic alkylation reaction. This reaction provides an efficient strategy for the enantioselective 1,2-difunctionalization of 1,3-dienes.
X. Wu, H.-C. Lin, M.-L. Li, L.-L. Li, Z.-Y. Han, L.-Z. Gong, J. Am. Chem. Soc., 2015, 137, 13467-13479.
A series of trialkylsilylated chiral aminophosphine ligands are prepared from (S)-prolinol and applied to a palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate with a dimethyl malonate-BSA-LiOAc system.
Y. Tanaka, T. Mino, K. Akita, M. Sakamoto, T. Fujita, J. Org. Chem., 2004, 69, 6679-6687.
The synthesis and properties of different planar chiral 1-phosphino-2-sulfenylferrocene ligands are reported. Very high enantioselectivities were obtained in the palladium-catalyzed allylic substitution of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate (ee's up to 97%) and nitrogen nucleophiles (ee's up to 99.5%) using the readily available tert-butylsulfenyl derivatives.
O. G. Mancheno, J. Priego, S. Cabrera, R. G. Arrayas, T. Llamas, J. C. Carretero, J. Org. Chem., 2003, 68, 3679-3686.
Bis-pyridylamides were used in a regioselective Molybdenium-catalyzed asymmetric allylation of carbonates. 4-substituted pyridyl ligands exhibited high regioselectivity and enantioselectivity, whereas 6-substituted ligands afforded no product under the same conditions.
O. Belda, C. Moberg, Synthesis, 2002, 1601-1603.
Simple dialkyl malonate esters exhibit limited scope as carbon nucleophiles in the Mitsunobu reaction. In contrast, bis(2,2,2-trifluoroethyl) malonates readily undergo dehydrative alkylation with primary and some secondary alcohols.
J. M. Takacs, Z. Xu, X.-T. Jiang, A. P. Leonov, G. C. Theriot, Org. Lett., 2002, 4, 3843-3845.