72013-65-1Relevant academic research and scientific papers
Room-Temperature Benzylic Alkylation of Benzylic Carbonates: Improvement of Palladium Catalyst and Mechanistic Study
Kuwano, Ryoichi,Yokogi, Masashi,Sakai, Ken,Masaoka, Shigeyuki,Miura, Takashi,Won, Sungyong
, p. 1568 - 1579 (2019/09/04)
The palladium catalyst for the nucleophilic substitution of benzyl carbonates was improved by using 1,1′-bis(diisopropylphosphino)ferrocene (DiPrPF) as the ligand. The [Pd(η3-C3H5)(cod)]BF4-DiPrPF catalyst allows the benzylic substitution with soft carbanions to proceed even at 30 °C, affording the desired products in high yields (up to 99% yield). Thermally unstable pyridylmethyl esters are employable as the electrophilic substrates for the benzylic alkylation with the improved catalyst. Furthermore, we investigated the mechanism of the catalytic benzylic alkylation by means of DiPrPF ligand. The palladium(0) complex bearing DiPrPF activates the benzylic C-O bond to form the (benzyl)palladium(II) intermediate at room temperature. The coordination mode of the benzyl ligand would be equilibrium between the η1- and η3-manner. The nucleophile would preferentially react with the η3-benzyl ligand to give the desired product.
Microwave-assisted dealkoxycarbonylation of α-mono- and α,α-disubstituted β-keto- and α-cyanoesters mediated by a silica gel bed
Guerrero-Caicedo, Alejandro,Soto-Martínez, Diana M.,Abonia, Rodrigo,Jaramillo-Gómez, Luz M.
, p. 2649 - 2657 (2018/02/19)
A new alternative protocol for the classical Krapcho reaction is reported herein, involving a microwave-assisted method, which replaces the typical aprotic polar solvent with a silica gel support along with the addition of only a few μL of DMF to enhance
Palladium catalyzed direct benzylation/allylation of malonates with alcohols-: In situ C-O bond activation
Cao, Xueqin,Zhang, Yugen
supporting information, p. 2638 - 2641 (2016/05/24)
High step- and atom-economy are the endlessly pursued in organic and pharmaceutical syntheses. Herein, a new method for directly coupling benzyl/allyl alcohols with malonates via a palladium catalyzed Tsuji-Trost type reaction was developed. The reaction was carried out in an organic carbonate solvent which would activate alcohols in situ, replacing the traditional pre-synthesized carbonates. The new process demonstrated high efficiency, high selectivity and high generality. A wide variety of mono-substituted and bis-substituted malonates were selectively produced under different conditions, and this method represents a more step- and atom-economical and environmentally benign synthetic protocol.
Activity of: N, N ′-dialkyl-2-trifluoromethylthioimidazolium salts as phase-transfer catalyst for the alkylation of active methylene compounds
Mizuta, Satoshi,Kitamura, Kanami,Nishi, Kodai,Hashimoto, Ryo,Usui, Toshiya,Chiba, Kenya
, p. 43159 - 43162 (2016/05/24)
We herein report the synthesis of N,N′-dialkyl-2-trifluoromethylthioimidazolium salts from thioureas using nucleophilic trifluoromethylating reagents. The activity of imidazolium salts as phase-transfer catalysts under solid-liquid phase conditions was in
Radical 3-exo-tet cyclization of 1,3-dihalopropanes with SmI2 to form cyclopropanes
Ohkita, Tsuyoshi,Tsuchiya, Yuhsuke,Togo, Hideo
, p. 7247 - 7251 (2008/12/20)
The preparation of 1,1-disubstituted and monosubstituted cyclopropanes from corresponding 2,2-disubstituted and 2-monosubstituted 1,3-dihalopropanes, respectively, with SmI2 in THF was efficiently carried out. The reaction mechanism was propose
Use of acetate as a leaving group in palladium-catalyzed nucleophilic substitution of benzylic esters
Yokogi, Masashi,Kuwano, Ryoichi
, p. 6109 - 6112 (2008/03/12)
The palladium complex prepared in situ from [Pd(η3-C3H5)(cod)]BF4 and bidentate phosphine DPPF was a good catalyst for the nucleophilic substitution of benzyl acetate. Significant acceleration of the palladium-catalyzed substitution was observed when an alcohol was employed as a reaction solvent. The palladium catalyst was effective for the benzylation of various stabilized carbanions, amines, and benzenesulfinate with benzylic acetates.
Palladium-catalyzed nucleophilic benzylic substitutions of benzylic esters
Kuwano, Ryoichi,Kondo, Yutaka,Matsuyama, Yosuke
, p. 12104 - 12105 (2007/10/03)
A palladium complex generated in situ from [Pd(η3-C3H5)(cod)]BF4 and DPPF is a good catalyst for benzylic alkylation of benzyl methyl carbonate with the carbanion of dimethyl malonates. The catalytic reaction is applicable to a wide range of the benzylations of benzylic esters with malonates. The catalytic activity was heavily affected by the bite angle of the bidentate phosphine ligand on palladium. DPEphos ligand is superior to DPPF in the case of palladium-catalyzed benzylic amination of benzylic esters. Copyright
Stereoselective Epoxidation of Phe-Gly and Phe-Phe Vinyl Isosteres
Jenmalm, Annika,Berts, Wei,Li, Yi-Lin,Luthman, Kristina,Csoeregh, Ingeborg,Hacksell, Uli
, p. 1139 - 1148 (2007/10/02)
Novel Phe-Gly and Phe-Phe isosteres have been synthesized.Vinylic isosteres of Phe-Gly and Phe-Phe were prepared by facile Julia reactions, and the resulting stereoisomers were isolated and epoxidized (m-chloroperbenzoic acid).Observed stereoselectivities
Piperidine containing malonic acid derivatives
-
, (2008/06/13)
Malonic acid derivatives of the formula STR1 wherein Z contain sterically hindered piperidines as stabilizers against light-induced degradation for organic material.
