4315-35-9Relevant academic research and scientific papers
Tandem Decarboxylative Cyclization/Alkenylation Strategy for Total Syntheses of (+)-Longirabdiol, (-)-Longirabdolactone, and (-)-Effusin
Zhang, Jianpeng,Li, Zijian,Zhuo, Junming,Cui, Yue,Han, Ting,Li, Chao
supporting information, p. 8372 - 8380 (2019/06/10)
Structurally complex and bioactive ent-kaurane diterpenoids have well-characterized biological functions and have drawn widespread attention from chemists for many decades. However, construction of highly oxidized forms of such diterpenoids still presents considerable challenges to synthetic chemists. Herein, we report the first total syntheses of C19 oxygenated spiro-lactone ent-kauranoids, including longirabdiol, longirabdolactone, and effusin. A concise synthesis of the common intermediate used for all three syntheses was enabled via three free-radical-based reactions: (1) a newly devised tandem decarboxylative cyclization/alkenylation sequence that forges the cis-19, 6-lactone concomitantly with vicinal alkenylation, (2) a Ni-catalyzed decarboxylative Giese reaction that constructs C10 quaternary center stereoselectively, and (3) a vinyl radical cyclization that generates a rigid bicyclo[3.2.1]octane. A series of late-stage oxidations from the common intermediate then provided each of the natural products in turn. Further biological evaluation of these synthetic natural products reveals broad anticancer activities.
CATALYST AND PROCESS FOR SYNTHESISING THE SAME
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Page/Page column 15, (2014/05/24)
The invention relates to a method for synthesising tethered ruthenium catalysts and novel tethered ruthenium catalysts obtainable by this methods. The method involves carrying out an "arene swapping" reaction avoiding the requirement to use complicated techniques making use of unreliable Birch reductions and unstable cyclodienyl intermediates.
Direct formation of tethered Ru(II) catalysts using arene exchange
Soni, Rina,Jolley, Katherine E.,Clarkson, Guy J.,Wills, Martin
supporting information, p. 5110 - 5113 (2013/10/22)
An 'arene exchange' approach has been successfully applied for the first time to the synthesis of Ru(II)-based 'tethered' reduction catalysts directly from their ligands in one step. This provides an alternative method for the formation of known complexes, and a route to a series of novel complexes. The novel complexes are highly active in both asymmetric transfer and pressure hydrogenation of ketones.
Hydroxyl radical generation via photoreduction of a simple pyridine N-oxide by an NADH analogue
Nakanishi, Ikuo,Nishizawa, Chiho,Ohkubo, Kei,Takeshita, Keizo,Suzuki, Kazuo T.,Ozawa, Toshihiko,Hecht, Sidney M.,Tanno, Masayuki,Sueyoshi, Shoko,Miyata, Naoki,Okuda, Haruhiro,Fukuzumi, Shunichi,Ikota, Nobuo,Fukuhara, Kiyoshi
, p. 3263 - 3265 (2007/10/03)
Photoreduction of pyridine N-oxide, which has a key structure of antitumor agents for hypoxic solid tumors, by 1-benzyl-1,4-dihydronicotinamide in deaerated aprotic media resulted in generation of hydroxyl radical, leading to the oxidation of salicylic acid to 2,3- and 2,5-dihydroxybenzoic acids, and catechol. The Royal Society of Chemistry 2005.
An N.M.R. Investigation of the Mills-Nixon Effect
Collins, Michael J.,Gready, Jill E.,Sternhell, Sever,Tansey, Charles W.
, p. 1547 - 1557 (2007/10/02)
The 4J coupling constant, previously established as a probe of bond order, was used to examine the bond orders in a series of ortho-bridged compounds: benzocyclopropene, 1,2-dihydrobenzocyclobutene, indan and tetralin.No evidence for sterically induced bond fixation (i.e. the Mills-Nixon effect) was found, but some evidence for electronic distortion in the corresponding benzylic ketones was observed.The experimental results are in accord with SCF/MO calculations.
Preparation of Highly Substituted 2-Pyridones by Reaction of Vinyl Isocyanates and Enamines
Rigby, James H.,Balasubramanian, N.
, p. 224 - 228 (2007/10/02)
A method for synthesis of highly substituted 2(1H)-pyridones is reported.Vinyl isocyanates, prepared from the corresponding α,β-unsaturated carboxylic acids, undergo cyclization with various enamines to furnish six-membered heterocycles.The methodology is exemplified by numerous examples.Application of this strategy is further illustrated by the synthesis of several aza steroid analogues.
