67461-24-9Relevant academic research and scientific papers
Towards the synthesis of the 4,19-diol derivative of (-)-mycothiazole: Synthesis of a potential key intermediate
Batt, Frederic,Fache, Fabienne
experimental part, p. 6039 - 6055 (2011/12/15)
The synthesis of a potential key intermediate for the synthesis of the 4,19-diol derivative of (-)-mycothiazole using convergent strategies is described in this paper. Several approaches have been tested, including cross metathesis and a Julia-Kocienski olefination. Finally, the formation of the 1,1-dialkyl-1,2-ethanediol motif through C4-C5 bond construction was realized by nucleophilic addition of a vinyl iodide derivative to a keto ester after halogen/lithium exchange followed by reduction of the resulting hydroxy ester. The synthesis of the allylic 1,1-dialkyl-1,2-ethanediol group, achieved by halogen/metal exchange followed by addition to aα-keto ester, is the key step of this convergent strategy towards a potential intermediate of mycothiazole-4,19-diol.
Cyclic acetals as precursors of substituted isochromans and naphthoxepines
Garcia, Daniel,Foubelo, Francisco,Yus, Miguel
, p. 507 - 519 (2008/09/18)
The reaction of 6,8-dioxabenzocycloheptenes 3 or 8,10-dioxacycloocta[de]naphthalenes 5 [easily prepared from the dibenzylic diols 1 and 4, respectively, and a carbonyl compound] with an excess of lithium and a catalytic amount of DTBB (2.5 mol %) in THF a
Oxidation of olefins by palladium(II). 18. Effect of reaction conditions, substrate structure and chiral ligand on the bimetallic palladium(II) catalyzed asymmetric chlorohydrin synthesis
El-Qisairi, Arab K,Qaseer, Hanan A,Henry, Patrick M
, p. 168 - 176 (2007/10/03)
The effect of electronic factors, solvent composition, identity of the chiral bidentate, and olefin structure on the yields and enantioselectivities of the asymmetric chlorohydrin synthesis were investigated. Electronic effects on the chlorohydrin reaction were tested by oxidation of phenyl allyl ether p-substituted by H, Cl, CH3O and CN. All species gave same similar yields and enantioselectivities indicating that electronic effects are not important. Varying the solvent composition of the THF-H2O mixtures indicated that the optimal solvent mixture contains more than 85% THF. Variation of added [Cl-] indicated that the added chloride had to be greater than 0.2 M for high yields and %ee's. Under ideal conditions the enantioselectivities of the chlorohydrins from the phenyl allyl ethers were more than 90%ee. Vinylacetic acid, methyl acrylate and trans-cinnamaldehyde were unreactive under the usual reaction conditions while 2-hydroxy-3-butene and allyl acetate give lower %ee's than did the phenyl allyl ethers. Styrene and α- methylstryrene gives comparable rates of reactions but the %ee's were lower with the latter. (2,6-Diisopropyl)phenyl allyl ether and 2- hydroxy-3-butene give high %ee's indicating that steric hindrance was not a major factor. All of the chiral bridging ligands tested gave satisfactory results except for DACH. A strange case was BZOX which did not give any induction at all. Structural studies showed the ligands are not large enough to bridge both Pd(II) in the bimetallic catalyst so one Pd(II) contained both ligand groups of the bidentate ligand and was thus unreactive. The other Pd(II) of the dimer was reactive but did not contain any chiral ligands to induce optical activity.
Synthesis of carbohydrates via tandem use of the osmium-catalyzed asymmetric dihydroxylation and enzyme-catalyzed aldol addition reactions
Henderson, Ian,Sharpless, K. Barry,Wong, Chi-Huey
, p. 558 - 561 (2007/10/02)
A new strategy is described for the asymmetric synthesis of carbohydrate derivatives via the tandem use of the osmium-catalyzed asymmetric dihydroxylation (AD) and aldolase-catalyzed aldol addition reactions. Both D- and L-forms of fructose, 6-deoxy-galacto-2-heptulose, and 6-phenyl-galacto-2-hexulose were synthesized to illustrate this methodology.
1,5-DIHYDRO-3H-2,4-BENZODIOXEPINE AS A NOVEL CARBONYL PROTECTING GROUP
Machinaga, Nobuo,Kibayashi, Chihiro
, p. 4165 - 4168 (2007/10/02)
A novel and facile protective group for carbonyl compounds as 1,5-dihydro-3H-2,4-benzodioxepine, which can be cleaved smoothly in a nonacidic manner by catalytic hydrogenolysis, has been demonstrated.
