125617-18-7Relevant academic research and scientific papers
A 3,4-dimercapto-3-cyclobutene-1,2-dione-chelated ruthenium carbene catalyst for: Z -stereoretentive/stereoselective olefin metathesis
Wang, Tao,Xie, Qingxiao,Guo, Weijie,Wu, Shutao,Zhang, Huiqing,Wang, Jianhui,Wu, Botao
, p. 6473 - 6483 (2019)
A ruthenium carbene catalyst chelated with a 3,4-dioxocyclobut-1-ene-1,2-dithiolate ligand was synthesized and its molecular structure was determined by single-crystal X-ray diffraction. The Ru catalyst had excellent catalytic activity with high yields and good Z/E ratios for the ring opening metathesis polymerization (ROMP) of norbornene (yield: 96%/Z/E: 86 : 14) and 1,5-cyclooctadiene (yield: 86%/Z/E: 91 : 9) and for ring opening cross metathesis (ROCM) reactions of norbornene/5-norbornene-2-exo, 3-exo-dimethanol with styrene (yields: 64%-92%/Z/E: 97 : 3-98 : 2) or 4-fluorostyrene (yield: 46%-94%/Z/E: 98 : 2). The catalyst also had high Z-stereoretentivity (91 : 9-98 : 2) for cross-metathesis (CM) reactions of terminal olefins with (Z)-2-butene-1,4-diol. More importantly, the catalyst had moderate Z-stereoselectivity for homometathesis reactions of terminal olefins giving cis-olefins as the major products (Z/E ratios of 70 : 30-77 : 23). Like other Ru carbene complexes, the catalyst tolerates many different functional groups. The presented data, supported by DFT calculations, show that our catalyst, bearing a chelating 3,4-dioxocyclobut-1-ene-1,2-dithiolate ligand, exhibits higher stability towards air than Hoveyda's stereoretentive complex systems.
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.
Enantioenriched Methylene-Bridged Benzazocanes Synthesis by Organocatalytic and Superacid Activations
Beaud, Rodolphe,Michelet, Bastien,Reviriot, Yasmin,Martin-Mingot, Agnès,Rodriguez, Jean,Bonne, Damien,Thibaudeau, Sébastien
supporting information, p. 1279 - 1285 (2019/12/24)
Achieving in a straightforward way the synthesis of enantioenriched elaborated three-dimensional molecules related to bioactive natural products remains a long-standing quest in organic synthesis. Enantioselective organocatalysis potentially offers a uniq
Photocatalyzed Diastereoselective Isomerization of Cinnamyl Chlorides to Cyclopropanes
Dykstra, Ryan,Gutierrez, Osvaldo,Martin, Robert T.,Tambar, Uttam K.,Troian-Gautier, Ludovic,Xu, Bin
, p. 6206 - 6215 (2020/04/27)
Endergonic isomerizations are thermodynamically unfavored processes that are difficult to realize under thermal conditions. We report a photocatalytic and diastereoselective isomerization of acyclic cinnamyl chlorides to strained cyclopropanes. Quantum mechanical calculations (uM06-2X and DLPNO), including TD-DFT calculations, and experimental studies provide evidence for the energy transfer from an iridium photocatalyst to the allylic chloride substrate followed by C-Cl homolytic cleavage. Subsequent Cla￠ radical migration forms a localized triplet 1,3-diradical intermediate that, after intersystem crossing, undergoes ring-closing to form the desired product. The mild reaction conditions are compatible with a broad range of functional groups to generate chlorocyclopropanes in high yields and diastereoselectivities. A more efficient process is developed by addition of a catalytic amount of a nickel complex, and we propose a novel role for this cocatalyst to recycle an allyl chloride byproduct generated in the course of the reaction. The reaction is also shown to be stereoconvergent, as an E/Z mixture of cinnamyl chlorides furnish the anti-chlorocyclopropane product in high diastereoselectivity. We anticipate that the use of a visible light activated photocatalyst to transform substrates in combination with a transition metal catalyst to recycle byproducts back into the catalytic cycle will provide unique opportunities for the discovery of new reactivity.
Synthesis of Allylsilanes via Nickel-Catalyzed Cross-Coupling of Silicon Nucleophiles with Allyl Alcohols
Yang, Bo,Wang, Zhong-Xia
supporting information, p. 7965 - 7969 (2019/10/19)
NiCl2(PMe3)2-catalyzed reaction of allyl alcohols with silylzinc reagents, including PhMe2SiZnCl, Ph2MeSiZnCl, and Ph3SiZnCl, was performed, achieving allylsilanes in high yields. Aryl- and heteroaryl-substituted allyl alcohols, (E)-3-arylprop-2-en-1-ols, 1-aryl-prop-2-en-1-ols, and (E)-1-phenylpent-1-en-3-ol can be employed in the transformation. A range of functional groups as well as heteroaryl groups were tolerated. Reaction exhibited high regioselectivity and E/Z-selectivity when 1- or 3-aryl-substituted allyl alcohols were used as the substrates. Reaction of chiral allyl alcohol, (S,E)-1-phenylpent-1-en-3-ol, yielded a configuration-inversion product (R,E)-dimethyl(phenyl)(1-phenylpent-1-en-3-yl)silane.
Palladium-catalyzed allylic C-H oxidation under simple operation and mild conditions
Guo, Yunlong,Shen, Zengming
supporting information, p. 3103 - 3107 (2019/03/26)
We discovered an effective and simple system (Pd/BQ/air/r.t.) for making allylic alcohols through Pd-catalyzed allylic C-H bond functionalization. This approach exhibits advantages due to its simple operation, mild conditions, and environmentally benign features. By modifying reaction conditions, it can be suitable for preparing unsaturated aldehydes, allylic esters, ethers, and amines.
Bioinspired Radical Stetter Reaction: Radical Umpolung Enabled by Ion-Pair Photocatalysis
Morack, Tobias,Mück-Lichtenfeld, Christian,Gilmour, Ryan
supporting information, p. 1208 - 1212 (2019/01/04)
A bioinspired, intermolecular radical Stetter reaction of α-keto acids and aldehydes is disclosed that is contingent on a formal “radical umpolung” concept. Enabled by secondary amine activation, electrostatic recognition ensures that the α-ketocarboxylic acids, which function as latent acyl radicals, are proximal to the in situ generated iminium salts. This photoactive contact ion pair is an electron donor–acceptor (EDA) complex, and undergoes facile single electron transfer (SET) and rapid decarboxylation prior to radical–radical recombination. Importantly, decarbonylation is mitigated by this strategy. The initial computational validation on which the process is predicated matches closely with experiment. Synergising organo- and photocatalysis activation principles finally expands the mechanistic and synthetic scope of the classic Stetter reaction to include α,β-unsaturated aldehydes as acceptors.
Boron-catalyzed CC functionalization of allyl alcohols
Rao, Santhosh,Kapanaiah, Raja,Prabhu, Kandikere Ramaiah
supporting information, p. 1301 - 1306 (2019/10/28)
Tris(pentafluorophenyl)borane-catalyzed CC bond functionalization of arylallyl alcohols using donor-acceptor carbenes is presented. The allylic hydroxyl group is found to assist the product formation by neighboring group participation providing a clue towards mechanistic understanding. This method can also be employed to effect homologation of allyl alcohols to homoallyl alcohols. Overall, this metal-free transformation presents a novel disconnection strategy towards carbon-carbon bond scission and formation.
Sequential Palladium-Catalyzed Allylic Alkylation/retro-Dieckmann Fragmentation Strategy for the Synthesis of α-Substituted Acrylonitriles
Katsina, Tania,Sharma, Sachi Prem,Buccafusca, Roberto,Quinn, Derek J.,Moody, Thomas S.,Arseniyadis, Stellios
supporting information, p. 9348 - 9352 (2019/11/20)
A straightforward synthesis of α-substituted acrylonitriles is described using 4-cyano-3-oxotetrahydro-thiophene (c-THT) as an acrylonitrile surrogate. This unprecedented two-step sequence featuring a palladium-catalyzed allylic alkylation (Pd-AA) and a retro-Dieckmann fragmentation provides a general entry into diversely substituted 1,4-dienes.
Palladium-Catalyzed Regioselective Aerobic Allylic C?H Oxygenation: Direct Synthesis of α,β-Unsaturated Aldehydes and Allylic Alcohols
Li, Chunsheng,Chen, Huoji,Li, Jianxiao,Li, Meng,Liao, Jianhua,Wu, Wanqing,Jiang, Huanfeng
supporting information, p. 1600 - 1604 (2018/03/05)
A protocol for the synthesis of α,β-unsaturated aldehydes and allylic alcohols from simple allylic hydrocarbons with water via palladium-catalyzed functionalization of allylic C?H bonds was described. Molecular oxygen is utilized as the sole oxidant in this oxygenation of terminal alkenes. This protocol features good functional group compatibility, broad substrate scope, and high atom- and step-economy. Moreover, the synthetic utility of this method can be highlighted by its application to the synthesis of ibuprofen, which is a highly potent analgesic. (Figure presented.).
