5402-28-8Relevant academic research and scientific papers
Heterogeneous Hydroxyl-Directed Hydrogenation: Control of Diastereoselectivity through Bimetallic Surface Composition
Shumski, Alexander J.,Swann, William A.,Escorcia, Nicole J.,Li, Christina W.
, p. 6128 - 6134 (2021/05/29)
Directed hydrogenation, in which product selectivity is dictated by the binding of an ancillary directing group on the substrate to the catalyst, is typically catalyzed by homogeneous Rh and Ir complexes. No heterogeneous catalyst has been able to achieve equivalently high directivity due to a lack of control over substrate binding orientation at the catalyst surface. In this work, we demonstrate that Pd-Cu bimetallic nanoparticles with both Pd and Cu atoms distributed across the surface are capable of high conversion and diastereoselectivity in the hydroxyl-directed hydrogenation reaction of terpinen-4-ol. We postulate that the OH directing group adsorbs to the more oxophilic Cu atom while the olefin and hydrogen bind to adjacent Pd atoms, thus enabling selective delivery of hydrogen to the olefin from the same face as the directing group with a 16:1 diastereomeric ratio.
Photoinduced Fragmentation Borylation of Cyclic Alcohols and Hemiacetals
Aggarwal, Varinder K.,Madhavachary, Rudrakshula,Noble, Adam,Shu, Chao
supporting information, p. 7213 - 7218 (2020/10/12)
A visible-light photoinduced fragmentation borylation of O-phthalimido cycloalkanols with bis(catecholato)diboron is described. Structurally diverse keto and formyloxy alkyl boronic esters are shown to be conveniently prepared by radical-mediated ring opening of cyclic alcohols and hemiacetals, respectively. The reactions proceed under mild conditions in the absence of additives or photocatalysts, display excellent functional group tolerance, and are shown to allow cleavage of 4-, 5-, 6-, and 7-membered ring substrates. The mechanism proceeds via sequential homolytic N-O and C-C bond cleavages, the latter of which involves β-scission of an alkoxy radical, generating a carbonyl and an alkyl radical that is trapped by the diboron reagent. Spectroscopic studies suggest direct photoexcitation of either the phthalimide or diboron substrates with blue light can initiate a radical chain mechanism.
Restricted rotation due to the lack of free space within a capsule translates into product selectivity: Photochemistry of cyclohexyl phenyl ketones within a water-soluble organic capsule
Kulasekharan, Revathy,Choudhury, Rajib,Prabhakar, Rajeev,Ramamurthy
supporting information; experimental part, p. 2841 - 2843 (2011/05/05)
The rotational mobility of organic guest molecules when included within a confined capsule is restricted and this feature could be translated into product selectivity as established with the photochemical behavior of cyclohexyl phenyl ketones. The Royal Society of Chemistry.
Reaction of Azoalkanes with Isolable Cation Radical Salts
Engel, Paul S.,Robertson, Donald M.,Scholz, John N.,Shine, Henry J.
, p. 6178 - 6187 (2007/10/02)
Three tertiary azoalkanes related in the sense acyclic, cyclic, and bicyclic are shown to evolve nitrogen upon oxidation with stable cation radical salts.Thus azo-tert-octane (ATO), 3,3,6,6-tetramethyl-1,2-diazacyclohexene (TMDAC), and 1,4-dimethyl-2,3-diazabicyclooct-2-ene (Me2DBO) react rapidly with thianthrenium perchlorate (Th(.1+)ClO4(1-)), tris(p-bromophenyl)aminium hexachloroantimonate (TBPA(.1+)SbCl6(1-)), and TBPA(.1+)SbF6(1-).The ether and olefin products, which are formed in high yield in CH2Cl2/MeOH solvent, are not those expected from the usual free-radical decomposition of azoalkanes but instead implicate carbocations.Althrough the reaction stoichiometry clearly requires 2 equiv of cation radical salt to one of azoalkane, the mechanism is not yet clearly defined.A complication in these studies is found in the ability of certain cation radical salts to oxidize more azoalkane than expected based on the 2:1 stoichiometry.
Functionalization of Saturated Hydrocarbons. Part 4. The Gif System for Selective Oxidation using Molecular Oxygen
Barton, Derek H. R.,Boivin, Jean,Gastiger, Michel,Morzycki, Jacek,Hay-Motherwell, Robyn S.,et al.
, p. 947 - 956 (2007/10/02)
Various systems for the selective oxidation of saturated hydrocarbons have been developed.These are based on the idea of an iron catalyst which is reduced by electron transfer and oxidized by molecular oxygen simultaneously in the presence of a source of protons.Four modifications of this system (the Gif system) have been devised of which the best (Gif IV) consists of an iron catalyst with metallic zinc as the reductant, acetic acid as the proton source and pyridine as the solvent.At room temperature, using oxygen or air, saturated hydrocarbons are oxidized selectively to ketones in isolated yields superior to those reported for comparable model systems.
ANHYDROUS FERRIC CHLORIDE ADSORBED ON SILICA GEL INDUCED RING ENLARGEMENT OF TERTIARY CYCLOBUTANOLS. SYNTHESIS OF ISOLAUROLENE AND DERIVATIVES, CAMPHOLENIC ETHER AND (+/-) CUPARENE
Fadel, A.,Salauen, J.
, p. 413 - 420 (2007/10/02)
The reagent obtained by mixing anhydrous FeCl3 and silica gel induced, in dry medium, dehydration and specific C4 -> C5 ring enlargement of tertiary cyclobutanols, cyclization of olefinic alcohols and cleavage of tetrahydropyranyl ethers.
