18653-57-1Relevant articles and documents
Chemo- A nd Regioselective Synthesis of Acyl-Cyclohexenes by a Tandem Acceptorless Dehydrogenation-[1,5]-Hydride Shift Cascade
Armstrong, Roly J.,Donohoe, Timothy J.,Matheau-Raven, Daniel,Smith, Lewis B.
supporting information, (2020/02/13)
An atom-economical methodology to access substituted acyl-cyclohexenes from pentamethylacetophenone and 1,5-diols is described. This process is catalyzed by an iridium(I) catalyst in conjunction with a bulky electron rich phosphine ligand (CataCXium A) which favors acceptorless dehydrogenation over conjugate reduction to the corresponding cyclohexane. The reaction produces water and hydrogen gas as the sole byproducts and a wide range of functionalized acyl-cyclohexene products can be synthesized using this method in very high yields. A series of control experiments were carried out, which revealed that the process is initiated by acceptorless dehydrogenation of the diol followed by a redox-neutral cascade process, which is independent of the iridium catalyst. Deuterium labeling studies established that the key step of this cascade involves a novel base-mediated [1,5]-hydride shift. The cyclohexenyl ketone products could readily be cleaved under mildly acidic conditions to access a range of valuable substituted cyclohexene derivatives.
Stereoselective synthesis of alicyclic ketones: A hydrogen borrowing approach
Armstrong, Roly J.,Akhtar, Wasim M.,Frost, James R.,Christensen, Kirsten E.,Stevenson, Neil G.,Donohoe, Timothy J.
, (2019/11/13)
A highly diastereoselective annulation strategy for the synthesis of alicyclic ketones from diols and pentamethylacetophenone is described. This process is mediated by a commercially available iridium(III) catalyst, and provides efficient access to a wide range of cyclopentane and cyclohexane products with high levels of stereoselectivity. The origins of diastereoselectivity in the annulation reaction have been explored by a series of control experiments, which provides an explanation for how each stereocentre around the newly forged ring is controlled.
Stereoselective Synthesis of Cyclohexanes via an Iridium Catalyzed (5 + 1) Annulation Strategy
Akhtar, Wasim M.,Armstrong, Roly J.,Frost, James R.,Stevenson, Neil G.,Donohoe, Timothy J.
, p. 11916 - 11920 (2018/09/27)
An iridium catalyzed method for the synthesis of functionalized cyclohexanes from methyl ketones and 1,5-diols is described. This process operates by two sequential hydrogen borrowing reactions, providing direct access to multisubstituted cyclic products with high levels of stereocontrol. This methodology represents a novel (5 + 1) strategy for the stereoselective construction of the cyclohexane core.
Photobiocatalytic alcohol oxidation using LED light sources
Rauch,Schmidt,Arends,Oppelt,Kara,Hollmann
supporting information, p. 376 - 379 (2017/08/14)
The photocatalytic oxidation of NADH using a flavin photocatalyst and a simple blue LED light source is reported. This in situ NAD+ regeneration system can be used to promote biocatalytic, enantioselective oxidation reactions. Compared to the traditional use of white light bulbs this method enables very significant reductions in energy consumption and CO2 emission.
Production of polyhydric alcohol (by machine translation)
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Paragraph 0058, (2017/04/28)
PROBLEM TO BE SOLVED: To provide a method for producing a high purity polyhydric alcohol by reduction of hemiacetal.SOLUTION: There is provided a method for producing a polyhydric alcohol, which comprises: (I) a step of hydrogenating hemiacetal represented by the following general formula (1) in the presence of a hydrogenation catalyst to obtain a reaction solution (I); (II) a step of adding an amine or a salt thereof to the reaction solution obtained in the step (I) to obtain a reaction solution (II); and (III) a step of separating a polyhydric alcohol from the reaction solution (II) obtained in the step (II). (wherein, Rto Reach independently represents a hydrogen atom or an alkyl group or an aryl group which may have a functional group; and n represents 1 or 2.)
Method for preparing 2-hydroxy-4-methyltetrahydropyran
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Paragraph 0083; 0102, (2017/07/21)
The invention relates to a method for preparing 2-hydroxy-4-methyltetrahydropyran (MHP) from using 3-methyl-3-buten-1-ol (IPEA) as a raw material under the catalysis of a rhodium compound and a tertiary phosphine ligand. After a reaction is finished, water extraction is performed for separating products from catalysts, wherein the rhodium catalyst and the tertiary phosphine ligand are reserved in an organic phase, the products are reserved in an aqueous phase, the conversion rate of IPEA can be as high as 99.7%, and the MHP selectivity of the products can be up tp 85.9%. The method solves the difficult problem that the costly rhodium catalyst is difficult to recover in a hydroformylation reaction process, and is favorable for industrial application.
PROCESS FOR PRODUCING POLYHYDRIC ALCOHOL
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Paragraph 0060, (2016/05/24)
A process for producing a polyhydric alcohol includes a step (I) of hydrogenating hemiacetal having a specific structure to obtain a reaction solution (I), and a step (II) of adding water to the reaction solution (I) obtained in the step (I) and further conducting hydrogenation.
Process for producing polyhydric alcohol
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Paragraph 0097; 0098, (2016/10/08)
A process for producing a polyhydric alcohol which comprises a step (I) in which a hemiacetal having a specific structure is hydrogenated to obtain a liquid reaction mixture (I) and a step (II) in which water is added to the liquid reaction mixture (I) obtained in the step (I) to further conduct hydrogenation.
Use of a semihollow-shaped triethynylphosphane ligand for efficient formation of six- and seven-membered ring ethers through gold(I)-catalyzed cyclization of hydroxy-tethered propargylic esters
Ito, Hideto,Harada, Ayumi,Ohmiya, Hirohisa,Sawamura, Masaya
supporting information, p. 647 - 652 (2013/04/10)
The formation of six- and seven-membered ring ethers from hydroxy-tethered propargylic esters was efficiently catalyzed by a cationic gold(I) complex with a semihollow-shaped triethynylphosphane ligand. This gold catalysis showed a tolerance toward the reactions of primary, secondary, and tertiary alcohol substrates with various substitution patterns. A sterically congested 2,2,6,6-tetraalkyl-substituted tetrahydropyran derivative as well as 6,6- and 7,6-fused bicyclic diethers were obtained in useful yields. In addition, the gold catalysis was applicable to the reaction of a sulfonamide-tethered propargylic ester to give a piperidine derivative. Copyright
Formation of quaternary carbon centers by highly regioselective hydroformylation with catalytic amounts of a reversibly bound directing group
Ueki, Yusuke,Ito, Hideto,Usui, Ippei,Breit, Bernhard
supporting information; experimental part, p. 8555 - 8558 (2011/09/19)
Directly opposing Keulemans rule! Phosphinites work as reversibly bound directing groups allowing for the first highly regioselective hydroformylation of 3-substituted homoallylic alcohols to construct quaternary carbon centers. This method enables the at
