84980-02-9Relevant academic research and scientific papers
Facile synthesis of (Z)-anti-homoallylic alcohols from 3-(pinacolatoboryl)allyl alcohols, aldehydes, and triorganoboranes via a palladium-catalyzed three-component reaction
Horino, Yoshikazu,Aimono, Ataru,Minoshima, Naoki,Abe, Hitoshi
, p. 3561 - 3564 (2016)
A palladium-catalyzed three-component reaction of 3-(pinacolatoboryl)allyl alcohols, aldehydes, and triorganoboranes was developed. The present protocol provides facile access to synthetically useful (Z)-anti-homoallylic alcohols with high diastereoselect
Palladium-Catalyzed Diastereoselective Synthesis of (Z)-Conjugated Enynyl Homoallylic Alcohols
Horino, Yoshikazu,Ishibashi, Mayo,Sakamoto, Juri,Murakami, Miki,Korenaga, Toshinobu
supporting information, p. 3592 - 3599 (2021/06/15)
The diastereoselective synthesis of anti-homoallylic alcohols bearing conjugated (Z)-enynes through a palladium-catalyzed three-component reaction is described. This reaction features a broad substrate scope, good functional group compatibility, and high levels of (Z)-alkene stereocontrol. In this reaction, Pd(0) functions as a catalyst in two fundamental steps of the tandem sequence: 1) the generation of a borylated π-allylpalladium species from bifunctional conjunctive reagents, inducing umpolung allylation of aldehydes, and 2) C(sp2)?C(sp) cross-coupling. Further transformations of the obtained products highlight their synthetic utility. (Figure presented.).
Synthesis of (Z)-alkene-containing linear conjugated dienyl homoallylic alcohols by a palladium-catalyzed three-component reaction
Horino, Yoshikazu,Sakamoto, Juri,Murakami, Miki,Sugata, Miki
, p. 1323 - 1327 (2020/08/21)
A synthesis of (Z)-alkene-containing linear conjugated dienyl homoallylic alcohols by using a palladium-catalyzed three-component reaction has been developed. This method shows good functional-group compatibility and generality, with high diastereoselectivity. Additionally, in many cases, the present method controls the alkene stereochemistry of the newly formed C-C bond and overcomes the inherent preference for (E)-alkene formation, giving (Z, E)- and (Z, Z)-products.
Visible-light-induced oxidative lignin c-c bond cleavage to aldehydes using vanadium catalysts
Liu, Huifang,Li, Hongji,Luo, Nengchao,Wang, Feng
, p. 632 - 643 (2020/01/02)
Lignin is the largest carrier of aromatics on earth, and its depolymerization can afford value-Added aromatic products. Direct cleavage of the C-C bonds in lignin linkages is significant, but it is challenging to obtain low-molecular-weight aromatic monomers. Herein, using vanadium catalysts under visible light, we selectively cleave the C-C bonds in β-1 and β-O-4 interlinkages occluded in lignin models and extracts by an oxidative protocol. Visible light irradiation triggered single electron transfer between the substrate and the catalyst, which further induced the selective Cα-Cβ bond cleavage and generated the final aromatic products through radical intermediates. Using this photocatalytic chemistry, the reactivity of lignin models and the selectivity of Cα-Cβ bond cleavage were significantly improved. More importantly, this protocol affords aromatic monomers through the fragmentation of organosolv lignins even at room temperature, indicating the potential of photocatalytic C-C bond cleavage of lignin linkages under ambient conditions.
Trialkylborane-Mediated Multicomponent Reaction for the Diastereoselective Synthesis of Anti-δ,δ-Disubstituted Homoallylic Alcohols
Horino, Yoshikazu,Murakami, Miki,Aimono, Ataru,Lee, Jun Hee,Abe, Hitoshi
supporting information, p. 476 - 480 (2019/01/14)
The trialkylborane/O2-mediated reaction of propargyl acetates having a tributylstannyl group at an alkyne terminus with aldehydes in a THF-H2O solvent system gave anti-δ,δ-disubstituted homoallylic alcohols with good to high diastereoselectivity. Intriguingly, two alkyl groups derived from trialkylborane were embedded into the reaction product. The trialkylborane plays a key role not only as a radical initiator but also as a source of alkyl radicals.
Metal-free, one-pot, sequential protocol for transforming ,-epoxy ketones to -hydroxy ketones and -methylene ketones
Hasegawa, Eietsu,Arai, Saki,Tayama, Eiji,Iwamoto, Hajime
, p. 1593 - 1600 (2015/02/19)
A new sequential, one-pot protocol for transforming 1,3-disubstituted 2,3-epoxy ketones to β;-hydroxy ketones and α-methylene ketones has been developed. Reaction of epoxy ketones with boron trifluoride etherate (BF3·OEt2) generates the cationic intermediates by regioselective epoxide ring opening and an acyl shift. Then, a treatment of these cations with 2-aryl-1,3-dimethylbenzimidazolines (DMBIH) results in formation of 1,2-disubstituted 3-hydroxy ketones. DMBIH serves as a hydride donor in the second step of this process. Finally, the β;-hydroxy ketones can be converted to 1,2-disubstituted 2-methylene ketones by treatment with methanesulfonic acid or a combination of methanesulfonyl chloride and triethylamine. Importantly, the sequential steps involved in formation of the α-methylene ketone products can be carried out in one pot.
Enantioselective synthesis of anti- and syn-β-hydroxy-α-phenyl carboxylates via boron-mediated asymmetric aldol reaction
Ramachandran, P. Veeraraghavan,Chanda, Prem B.
supporting information, p. 3152 - 3154 (2013/06/05)
A reagent-controlled, diastereo- and enantioselective synthesis of anti- and syn-β-hydroxy-α-phenyl carboxylates has been achieved by the proper choice of solvent, temperature, alkoxy group, and amine for the diisopinocampheylboron-mediated asymmetric enolization-aldolization of phenylacetates. The pure diastereomers can be readily separated by column chromatography.
The role of the α-stereogenic center in the control of stereoselection in the reduction of α-alkyl-β-hydroxy ketones: A highly diastereoselective protocol for the synthesis of 1,2-syn-2-alkyl-1,3-diols
Bartoli, Giuseppe,Bellucci, Maria C.,Bosco, Marcella,Dalpozzo, Renato,Marcantoni, Enrico,Sambri, Letizia
, p. 2590 - 2598 (2007/10/03)
Accurate investigations on the role played by an α-stereogenic center in controlling the reduction of various classes of β-hydroxy ketones allowed us to set up a general and highly diastereoselective protocol for the synthesis of 2-alkyl-1,3-diols with 1,
Highly diastereoselective reduction of α-alkyl-β-hydroxy ketones with sodium and lithium boron hydrides via their titanium alcoholates
Bartoli, Giuseppe,Bellucci, M. Cristina,Bosco, Marcella,Dalpozzo, Renato,Marcantoni, Enrico,Sambri, Letizia
, p. 2845 - 2848 (2007/10/03)
The reduction of α-alkyl-β-hydroxy ketones is highly syn-selective if carded out in THF on their Ti-alcoholate complexes with LiBH4 or L- Selectride or N-selectride depending on the bulkiness of the group bound to the carbonyl group.
Intramolecular C-H insertion reactions of boroxy Fischer carbene complexes. Regio-and diastereoselective modification of terpenes
Barluenga, Jose,Rodriguez, Felix,Vadecard, Jerome,Bendix, Maximilian,Fananas, Francisco J.,Lopez-Ortiz, Fernando,Rodriguez, Miguel A.
, p. 8776 - 8782 (2007/10/03)
In-situ-generated dialkylboroxy and diaminoboroxy Fischer carbene complexes lead to oxaborolane or oxazaborolidine derivatives via an intramolecular C-H insertion reaction. Further oxidation of these intermediates yields 1,3-diol or 1,2-amino alcohol derivatives. Diastereoselectivities as high as 99% are reached when starting from boroxy Fischer carbene complexes derived from terpenes, which represents a regio-and diastereoselective modification of this type of natural product. The influence of the Cβ substituents relative to the boron atom on the reaction path is studied, and a mechanism is proposed after identification of an intermediate by NMR. In addition, theoretical calculations show the presence of a boron-metal interaction, which could result as key step to the C-H insertion reaction.
