3461-50-5Relevant academic research and scientific papers
Oxoammonium-Mediated Allylsilane–Ether Coupling Reaction
Carlet, Federica,Bertarini, Greta,Broggini, Gianluigi,Pradal, Alexandre,Poli, Giovanni
supporting information, p. 2162 - 2168 (2021/04/02)
A new C(sp3)?H functionalization reaction consisting of the oxidative α-allylation of allyl- and benzyl- methyl ethers has been developed. The C?C coupling could be carried out under mild conditions thanks to the use of cheap and green oxoammonium salts. The scope of the reaction was studied over 27 examples, considering the nature of the substituents on the two coupling partners.
Dramatic Effect of γ-Heteroatom Dienolate Substituents on Counterion Assisted Asymmetric Anionic Amino-Cope Reaction Cascades
Das, Pradipta,Delost, Michael D.,Qureshi, Munaum H.,Bao, Jianhua,Fell, Jason S.,Houk, Kendall N.,Njardarson, Jon T.
supporting information, p. 5793 - 5804 (2021/05/07)
We report a dramatic effect on product outcomes of the lithium ion enabled amino-Cope-like anionic asymmetric cascade when different γ-dienolate heteroatom substituents are employed. For dienolates with azide, thiomethyl, and trifluoromethylthiol substituents, a Mannich/amino-Cope/cyclization cascade ensues to form chiral cyclohexenone products with two new stereocenters in an anti-relationship. For fluoride-substituted nucleophiles, a Mannich/amino-Cope cascade proceeds to afford chiral acyclic products with two new stereocenters in a syn-relationship. Bromide- and chloride-substituted nucleophiles appear to proceed via the same pathway as the fluoride albeit with the added twist of a 3-exo-trig cyclization to yield chiral cyclopropane products with three stereocenters. When this same class of nucleophiles is substituted with a γ-nitro group, the Mannich-initiated cascade is now diverted to a β-lactam product instead of the amino-Cope pathway. These anionic asymmetric cascades are solvent- and counterion-dependent, with a lithium counterion being essential in combination with etheral solvents such as MTBE and CPME. By altering the geometry of the imine double bond from E to Z, the configurations at the R1 and X stereocenters are flipped. Mechanistic, computational, substituent, and counterion studies suggest that these cascades proceed via a common Mannich-product intermediate, which then proceeds via either a chair (X = N3, SMe, or SCF3) or boat-like (X = F, Cl, or Br) transition state to afford amino-Cope-like products or β-lactam in the case of X = NO2.
Recyclable and reusable PdCl2(PPh3)2/PEG-400/H2O system for the hydrophenylation of alkynes with sodium tetraphenylborate
Liu, Rong,Zhang, Tingli,Huang, Bin,Cai, Mingzhong
, p. 172 - 178 (2020/07/04)
A stable and efficient PdCl2(PPh3)2/PEG-400/H2O catalytic system for the hydrophenylation reaction of alkynes has been developed. In the presence of 3 mol% PdCl2(PPh3)2 and 2 equiv. of HOAc, the hydrophenylation of both terminal and internal alkynes with sodium tetraphenylborate proceeded smoothly in a mixture of PEG-400 and water at room temperature or 50 °C to afford a variety of phenyl-substituted alkenes in moderate to high yields. The isolation of the products was easily performed by extraction with petroleum ether, and the PdCl2(PPh3)2/PEG-400/H2O system could be readily recycled and reused six times without apparent loss of catalytic activity.
Copper-Catalyzed 1,2-Methoxy Methoxycarbonylation of Alkenes with Methyl Formate
Budai, Balázs,Leclair, Alexandre,Wang, Qian,Zhu, Jieping
supporting information, p. 10305 - 10309 (2019/06/27)
Reported here is a copper-catalyzed 1,2-methoxy methoxycarbonylation of alkenes by an unprecedented use of methyl formate as a source of both the methoxy and the methoxycarbonyl groups. This reaction transforms styrene and its derivatives into value-added β-methoxy alkanoates and cinnamates, as well as medicinally important five-membered heterocycles, such as functionalized tetrahydrofurans, γ-lactones, and pyrrolidines. A ternary β-diketiminato-CuI-styrene complex, fully characterized by NMR spectroscopy and X-ray crystallographic analysis, is capable of catalyzing the same transformation. These findings suggest that pre-coordination of electron-rich alkenes to copper might play an important role in accelerating the addition of nucleophilic radicals to electron-rich alkenes, and could have general implications in the design of novel radical-based transformations.
DMAP-Catalyzed [4 + 2] Cycloaddition of α,β-Unsaturated Carboxylic Acids with Ketones for Synthesis of α,β-Unsaturated δ-Lactones
Jin, Jinghai,Xu, Qinchang,Deng, Weiping
supporting information, p. 397 - 400 (2017/04/27)
The DMAP-catalyzed [4 + 2] cycloaddition of α,β-unsaturated carboxylic acids with ketones furnishing α,β-unsaturated δ-lactones in good yields (up to 80%) is described, which is the first example of remote γ-C(sp3)-H activation of α,β-unsaturated carboxylic acids facilitated by DMAP, a pyridine-based catalyst. Copyright
Highly efficient synthesis of chiral aromatic ketones: Via Rh-catalyzed asymmetric hydrogenation of β,β-disubstituted enones
Zhang, Tao,Jiang, Jun,Yao, Lin,Geng, Huiling,Zhang, Xumu
supporting information, p. 9258 - 9261 (2017/08/22)
A succinct and efficient protocol was developed for the synthesis of chiral aromatic ketones via asymmetric hydrogenation of β,β-disubstituted enones with rhodium catalysts based on chiral bisphosphine thiourea ligands. A series of substrates (17 examples) was smoothly catalyzed to afford the corresponding chiral aromatic ketones in high conversions (>99%) with excellent enantioselectivities (up to 96% ee).
Rhodium-Catalyzed Asymmetric Hydrogenation of α,β-Unsaturated Carbonyl Compounds via Thiourea Hydrogen Bonding
Wen, Jialin,Jiang, Jun,Zhang, Xumu
supporting information, p. 4451 - 4453 (2016/09/28)
The strategy of secondary interaction enables enantioselectivity for homogeneous hydrogenation. By introducing hydrogen bonding of substrates with thiourea from the ligand, α,β-unsaturated carbonyl compounds, such as amides and esters, are hydrogenated wi
Palladium-Catalyzed Arylation of Olefins by Triarylphosphines via C-P Bond Cleavage
Lu, Dapeng,Xu, Yu,Liu, Wenjing,Guo, Lijuan,Sun, Xingxia
, p. 116 - 122 (2015/10/19)
C-H Arylation of olefins by triarylphosphines via C-P bond cleavage has been achieved with either Pd0 or PdII catalysts. A variety of olefins and triarylphosphines are tolerated, and we inferred that both Pd0 and PdII could function directly without pre-oxidation or pre-reduction.
Gallium-assisted transfer hydrogenation of alkenes
Michelet, Bastien,Bour, Christophe,Gandon, Vincent
supporting information, p. 14488 - 14492 (2015/04/16)
We report a rare case of alkene transfer hydrogenation using a main-group compound instead of a transition-metal complex as catalyst. We disclosed that 1, 4-cyclo-hexadiene can be used as H2 surrogate towards olefin reduction in the presence of [IPrGaCl2][SbF6]. Hydrogenative cycli-zations have also been carried out because this cationic gallium complex is also a potent hydroarylation catalyst.
Palladium-catalyzed arylation of enoates with iodobenzene: Stereoselective synthesis of trisubstituted olefins
De Fernandes, Talita A.,Vaz, Boniek G.,Da Silva, Alcides J.M.,Esteves, Pierre M.,Eberlin, Marcos N.,Costa, Paulo R.R.
, p. 500 - 506 (2013/08/25)
The Heck reaction between E- and Z-enoates and iodobenzene was studied in the presence of Pd(OAc)2. The stereochemistry in resulting adducts was dependent on the enoate geometry (stereospecific reaction). Best yields were obtained from Z-isomer
