52188-73-5Relevant academic research and scientific papers
Chemoselective and stereoselective lithium carbenoid mediated cyclopropanation of acyclic allylic alcohols
Durán-Pe?a,Flores-Giubi,Botubol-Ares,Harwood,Collado,Macías-Sánchez,Hernández-Galán
, p. 2731 - 2741 (2016)
The reaction of geraniol with different lithium carbenoids generated from n-BuLi and the corresponding dihaloalkane has been evaluated. The reaction occurs in a chemo and stereoselective manner, which is consistent with a directing effect from the oxygen of the allylic moiety. Furthermore, a set of polyenes containing allylic hydroxyl or ether groups were chemoselectively and stereoselectively converted into the corresponding gem-dimethylcyclopropanes in one single step in moderate to good yields mediated by a lithium carbenoid generated in situ by the reaction of n-BuLi and 2,2-dibromopropane.
Vanadium-Catalyzed Oxidative Debenzylation of O-Benzyl Ethers at ppm Level
Urgoitia, Garazi,SanMartin, Raul,Herrero, María Teresa,Domínguez, Esther
supporting information, p. 3307 - 3312 (2016/10/21)
An advantageous methodology for the oxidative debenzylation of ethers has been developed. Very low amounts of a catalyst system based on vanadyl acetylacetonate and a triazole type pincer ligand allow the selective oxidative cleavage of a number of O-benzyl ethers in the presence of oxygen as the sole oxidant. The methodology tolerates a number of functional groups such as halo-, alkoxy-, or trifluoromethylarenes, alkyne, alkene, ether, and acetal units. Large-scale deprotections can be also carried out by the optimized procedure, which is amenable to enantioenriched reactants as well. (Figure presented.).
Titanium carbenoid-mediated cyclopropanation of allylic alcohols: Selectivity and mechanism
Durán-Pe?a,Botubol-Ares,Hanson,Hernández-Galán,Collado
, p. 6325 - 6332 (2015/06/08)
A new method for the chemo- and stereoselective conversion of allylic alcohols into the corresponding cyclopropane derivatives has been developed. The cyclopropanation reaction was carried out with an unprecedented titanium carbenoid generated in situ from Nugent's reagent, manganese and methylene diiodide. The reaction involving the participation of an allylic hydroxyl group, proceeded with conservation of the alkene geometry and in a high diastereomeric excess. The scope, limitations and mechanism of this metal-catalysed reaction are discussed. This journal is
New methodology for the conversion of epoxides to alkenes
Wu, Feng-Ling,Ross, Benjamin P.,McGeary, Ross P.
experimental part, p. 1989 - 1998 (2010/06/15)
Epoxides have been transformed in good yields to alkenes by a process involving (i) ring-opening of the epoxide with 2-mercaptobenzothiazole, (ii) oxidation of the derived ss-hydroxy thioethers to the corresponding sulfones, and (iii) thermal or base-promoted fragmentation of these sulfones to alkenes. The stereochemistry of the starting epoxide is transfer-red faithfully to the alkene product, because of the SN2 epoxide ring-opening reactions and the antiperiplanar SO2 elimination reaction of the ss- alkoxysulfinate intermediates. This methodology may form the basis of a new protecting group strategy for alkenes.
Oxidative cyclization of diols derived from 1,5-dienes: Formation of enantiopure cis-tetrahydrofurans by using catalytic osmium tetroxide; formal synthesis of (+)-cis-solamin
Donohoe, Timothy J.,Butterworth, Sam
, p. 4766 - 4768 (2007/10/03)
(Chemical Equation Presented) High yields and high levels of stereocontrol are observed in the oxidative cyclization of vicinal diols using catalytic amounts of a transition metal (see scheme; TFA = trifluoroacetic acid). The product stereochemistry is co
A practical synthesis of (-)-kazusamycin A (revised)
Zhou, Shengfeng,Chen, Huaxiang,Liao, Wensheng,Chen, Shu-Hui,Li, Ge,Ando, Ryoichi,Kuwajima, Isao
, p. 6341 - 6344 (2007/10/03)
We describe herein a stereo-controlled and practical synthesis of three key building blocks, namely Segment AB′, Segment D, and Segment E′ needed for the total synthesis of (-)-kazusamycin A.
Chemoenzymatic synthesis of (E)-3,7-dimethyl-2-octene-1,8-diol isolated from the hairpencils of male Danaus chrysippus (African Monarch)
Takabe, Kunihiko,Mase, Nobuyuki,Hashimoto, Hiroya,Tsuchiya, Atsushi,Ohbayashi, Takashi,Yoda, Hidemi
, p. 1967 - 1969 (2007/10/03)
The synthesis of (E)-3,7-dimethyl-2-octene-1,8-diol (1), which was isolated from the hairpencils of male Danaus chrysippus (African Monarch), was investigated. The key step of the sequence involves asymmetric desymmetrization of the 1,3-propanediol 7 with
A novel type of Pd/C-catalyzed hydrogenation using a catalyst poison: Chemoselective inhibition of the hydrogenolysis for O-benzyl protective group by the addition of a nitrogen-containing base
Sajiki, Hironao,Hirota, Kosaku
, p. 13981 - 13996 (2007/10/03)
A mild and chemoselective hydrogenation method for a variety of reducible functional groups distinguishing front aliphatic and aromatic' benzyl ethers was accomplished by the addition of an appropriate nitrogen- containing base to the Pd/C-catalyzed hydrogenation system.
Total synthesis of (+)-curacin A, a marine cytotoxic agent
Hoemann, Michael Z.,Agrios, Konstantinos A.,Aube, Jeffrey
, p. 11087 - 11098 (2007/10/03)
The total synthesis of curacin A, a cytotoxic agent that interacts with the colchicine binding site on tubulin, is described. The convergent synthesis utilizes natural product and chiral pool starting materials (geraniol, serine) and asymmetric synthesis
Total Syntheses of Fungal Metabolites and Functionalized Furanones
Chen, Kau-Ming,Semple, J. Edward,Joullie, Madeleine M.
, p. 3997 - 4005 (2007/10/02)
Simple, efficient syntheses of the fungal metabolites colletochlorin D and (+/-)-ascofuranone and one of its stereoisomers are described.Our investigations of functionalized furanones also enabled us to develop a nine-step (22percent overall yield) synthe
