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 Cyclohexanes via an Iridium Catalyzed (5 + 1) Annulation Strategy
Akhtar, Wasim M.,Armstrong, Roly J.,Frost, James R.,Stevenson, Neil G.,Donohoe, Timothy J.
supporting information, 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.
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.
