3968-87-4Relevant academic research and scientific papers
Cross β-alkylation of primary alcohols catalysed by DMF-stabilized iridium nanoparticles
Kobayashi, Masaki,Yamaguchi, Hiroki,Suzuki, Takeyuki,Obora, Yasushi
supporting information, p. 1950 - 1954 (2021/03/16)
A simple method for the cross β-alkylation of linear alcohols with benzyl alcohols in the presence of DMF-stabilized iridium nanoparticles was developed. The nanoparticles were prepared in one-step and thoroughly characterized. Furthermore, the optimum reaction conditions have a wide substrate scope and excellent product selectivity.
Synthesis and olfactory evaluation of optically active β-alkyl substituted γ-lactones and whiskey lactone analogues
Kato, Daiki,Kawasaki, Masashi,Morita, Yuko,Okada, Takuya,Tanaka, Yasuo,Toyooka, Naoki
supporting information, (2020/02/22)
Optically active β-alkyl substituted γ-lactones and whiskey lactone analogues were synthesized, and the odor properties were evaluated. During the preparation of the chiral intermediates, we found good reaction conditions for the highly enantioselective esterification of 3-arylmethyl-2-methyl-1-propanols to kinetically resolve them. The results of the olfactory evaluations of the synthesized lactones revealed that the alkyl groups on the γ-lactone rings played an important role for the odor profiles.
Application of Trimethylgermanyl-Substituted Bisphosphine Ligands with Enhanced Dispersion Interactions to Copper-Catalyzed Hydroboration of Disubstituted Alkenes
Xi, Yumeng,Su, Bo,Qi, Xiaotian,Pedram, Shayun,Liu, Peng,Hartwig, John F.
supporting information, p. 18213 - 18222 (2020/12/04)
We report the incorporation of large substituents based on heavy main-group elements that are atypical in ligand architectures to enhance dispersion interactions and, thereby, enhance enantioselectivity. Specifically, we prepared the chiral biaryl bisphosphine ligand (TMG-SYNPHOS) containing 3,5-bis(trimethylgermanyl)phenyl groups on phosphorus and applied this ligand to the challenging problem of enantioselective hydrofunctionalization reactions of 1,1-disubtituted alkenes. Indeed, TMG-SYNPHOS forms a copper complex that catalyzes hydroboration of 1,1-disubtituted alkenes with high levels of enantioselectivity, even when the two substituents are both primary alkyl groups. In addition, copper catalysts bearing ligands possessing germanyl groups were much more active for hydroboration than one derived from DTBM-SEGPHOS, a ligand containing 3,5-di-tert-butyl groups and widely used for copper-catalyzed hydrofunctionalization. This observation led to the identification of DTMGM-SEGPHOS, a bisphosphine ligand bearing 3,5-bis(trimethylgermanyl)-4-methoxyphenyl groups as the substituents on the phosphorus, as a new ligand that forms a highly active catalyst for hydroboration of unactivated 1,2-disubstituted alkenes, a class of substrates that has not readily undergone copper-catalyzed hydroboration previously. Computational studies revealed that the enantioselectivity and catalytic efficiency of the germanyl-substituted ligands is higher than that of the silyl and tert-butyl-substituted analogues because of attractive dispersion interactions between the bulky trimethylgermanyl groups on the ancillary ligand and the alkene substrate and that Pauli repulsive interactions tended to decrease enantioselectivity.
Ru-Catalyzed Cross-Dehydrogenative Coupling between Primary Alcohols to Guerbet Alcohol Derivatives: With Relevance for Fragrance Synthesis
Manojveer, Seetharaman,Salahi, Saleh,Wendt, Ola F.,Johnson, Magnus T.
, p. 10864 - 10870 (2018/09/06)
A simple method has been developed for the cross dehydrogenative coupling between two different primary alcohols using readily available RuCl2(PPh3)3 as a precatalyst through the borrowing-hydrogen approach. The present methodology is applicable to a large variety of alcohol derivatives including long chain aliphatic alcohols and heteroaryl alcohols. In addition, the methodology was applied in a straightforward protocol to synthesize commercially available fragrances such as Rosaphen and Cyclamenaldehyde in good yields.
Nickel-Catalyzed Asymmetric Kumada Cross-Coupling of Symmetric Cyclic Sulfates
Eno, Meredith S.,Lu, Alexander,Morken, James P.
, p. 7824 - 7827 (2016/07/11)
Nickel-catalyzed enantioselective cross-couplings between symmetric cyclic sulfates and aromatic Grignard reagents are described. These reactions are effective with a broad range of substituted cyclic sulfates and deliver products with asymmetric tertiary carbon centers. Mechanistic experiments point to a stereoinvertive SN2-like oxidative addition of a nickel complex to the electrophilic substrate.
First practical cross-alkylation of primary alcohols with a new and recyclable impregnated iridium on magnetite catalyst
Cano, Rafael,Yus, Miguel,Ramon, Diego J.
supporting information; experimental part, p. 7628 - 7630 (2012/09/25)
A new impregnated iridium on magnetite catalyst has been prepared, characterized, used and recycled, up to ten times with practically the same activity, for the first practical cross-alkylation of primary alcohols. The catalyst showed a wide reaction scope, is easy to prepare and handle, and it could be removed from the reaction medium just by magnetic sequestering.
LiAlH4-induced reductive dephosphonylation of αα-dialkyl triethyl β-phosphonyl esters: Mechanistic study and synthetic application
Zhu, Jia-Liang,Bau, Jr-Sheng,Shih, You-Cheng
experimental part, p. 863 - 866 (2012/05/20)
Treatment of αα-dialkyl triethyl β-phosphonyl esters with LiAlHin CHlTHF caused the one-pot dephosphonylation and reduction to yield the corresponding primary alcohols bearing a controllable β secondary carbon center. Mechanistic study has revealed that the LiAlHinduced dephosphonylation should occur first with the assistance of the carboxylate group, and the hydrogen source of the resultant new C-H bond is LiAlH. Georg Thieme Verlag Stuttgart . New York.
Asymmetric synthesis of novel α-amino acids with β-branched side chains
Zhang, Minsheng,Porte, Alex,Diamantidis, George,Sogi, Kimberly,Kubrak, Dennis,Resnick, Lynn,Mayer, Scott C.,Wang, Zheng,Kreft, Anthony F.,Harrison, Boyd L.
, p. 2401 - 2403 (2008/02/03)
An asymmetric synthesis of α-amino acids with novel β-branched side chains has been implemented. The syntheses feature a p-toluenesulfinylimine induced chiral Strecker approach and were found to be applicable to the introduction of both aliphatic and aromatic β-branched sidechains for preparation of previously unknown α-amino acids.
Highly efficient alkylation of epoxides with R3Al/H2O systems based on the double activation of epoxy oxygens
Abe, Noriko,Hanawa, Hideo,Maruoka, Keiji,Sasaki, Minoru,Miyashita, Masaaki
, p. 5369 - 5372 (2007/10/03)
Alkylation of epoxides can be effected with trialkylaluminum/water system, which is much superior to the parent trialkylaluminum. Bidentate bis(dialkyl)aluminoxanes and their hypothetical analogues seem to be active species for the double activation of epoxy substrates. Such double-activation ability is emphasized using several synthetic examples in comparison with the corresponding monodentate derivatives. The double coordination complex formation of bidentate (Me2Al)2O is characterized with THF by 1H and 13C NMR spectroscopy.
THE ATE COMPLEXES OF ALUMINIUM. REACTIVITY AND STEREOSELECTIVITY WITH RESPECT TO EPOXIDES AND CARBONYL COMPOUNDS. CATALYTIC ACTIVATION BY SALTS OF TRANSITION METALS
Boireau, G.,Abenhaim, D.,Henry-Basch, E.
, p. 3061 - 3070 (2007/10/02)
When used in non-coordinating solvents (hydrocarbons) NaAlEt4 and LiAlnBu4 are good alkylation agents for epoxides.The presence of catalytic quantities of transition-metal salts, particularly NiCl2 or NiBr2, greatly accelerate the reactions, making them possible within a reasonable time in the case of disubstituted epoxides such as cyclohexene oxide, 2-3 epoxybutane, 1 phenyl-2,3-epoxybutane.In the case of aliphatic epoxides, dialkylmagnesium, NaAlEt4 and LiAlnBu4 lead mainly to alkylation of the least substituted carbon of the epoxide ring; while in the case of epoxides with C-O bond in the benzyl position, it is this carbon that is alkylated.The reaction always proceeds by total inversion of the configuration of the carbon in the epoxide ring, namely the site of the alkylation. NaAlEt4 is also good agent for alkylating carbonyl compounds when used in solvents of low basicity such as diethylether, or in totally non-coordinating solvents such as the hydrocarbons.The yields of the alcohol are greatly improved by using catalytic quantities of NiCl2.The behaviour of NaAlEt4 with 2-phenylpropanol is quite remarkable: in diethylether NaAl-Et4 gives predominantly the pair of enantiomers predicted by Cram's rule and with greater stereoselectivity than if EtMgBr was used, while in pentane the reaction is no longer stereoselective.Finally, with a cyclic ketone, 4-t-butylcyclohexanone, NaAlEt4 in diethylether and in hexane in the presence of NiCl2 gives predominantly the equatorial alcohol resulting from an axial attack, which is generally not favoured at all.
