41049-36-9Relevant academic research and scientific papers
The Direct Conversion of α-Hydroxyketones to Alkynes
Ghiringhelli, Francesca,Nattmann, Lukas,Bognar, Sabine,Van Gemmeren, Manuel
, p. 983 - 993 (2019/01/24)
Alkynes are highly important functional groups in organic chemistry, both as part of target structures and as versatile synthetic intermediates. In this study, a protocol for the direct conversion of α-hydroxyketones to alkynes is reported. In combination with the variety of synthetic methods that generate the required starting materials by forming the central C-C bond, it enables a highly versatile fragment coupling approach toward alkynes. A broad scope for this novel transformation is shown alongside mechanistic insights. Furthermore, the utility of our protocol is demonstrated through its application in concert with varied α-hydroxyketone syntheses, giving access to a broad spectrum of alkynes.
Enantioselective aerobic oxidation of α-hydroxy-ketones catalyzed by oxidovanadium(V) methoxides bearing chiral, N-salicylidene- tert -butylglycinates
Chen, Chien-Tien,Kao, Jun-Qi,Salunke, Santosh B.,Lin, Ya-Hui
, p. 26 - 29 (2011/03/22)
Chiral oxidovanadium(V) methoxides prepared from 3,5-disubstituted-N- salicylidene-l-tert-butylglycines and vanadyl sulfate in air-saturated MeOH serve as highly enantioselective catalysts for asymmetric aerobic oxidations and kinetic resolution of alkyl, aryl, and heteroaryl α-hydroxy-ketones with differed α-substituents at ambient temperature in toluene or TBME (tert-butyl methyl ether). The best scenarios involve the use of complexes which bear the tridendate templates derived from 3,5-diphenyl- or 3-o-biphenyl-5-nitro-salicyaldehyde. The kinetic resolution selectivities of the aerobic oxidation process are in the range of 12 to >1000 based on the selectivity factors (krel).
Aerobic oxidative iodination of ketones catalysed by sodium nitrite "on water" or in a micelle-based aqueous system
Stavber, Gaj,Iskra, Jernej,Zupan, Marko,Stavber, Stojan
experimental part, p. 1262 - 1267 (2010/05/02)
Selective and efficient aerobic oxidative iodination of ketones in aqueous media was achieved by using molecular iodine as the source of iodine atoms, air as the terminal oxidant, sodium nitrite (NaNO2) as the catalyst and H2SO4
Al Lewis acid-catalyzed regiodivergent 1,2-rearrangement of α-siloxy aldehydes: scope and mechanism
Ohmatsu, Kohsuke,Tanaka, Takayuki,Ooi, Takashi,Maruoka, Keiji
experimental part, p. 7516 - 7522 (2009/12/04)
Regiodivergent 1,2-rearrangement of α-siloxy aldehydes bearing α-aryl and α-alkyl substituents into α-siloxy ketones has been realized by using different Al Lewis acid catalyst/solvent systems. The scope of this unprecedented protocol has been investigate
Complete switch of migratory aptitude in aluminum-catalyzed 1,2-rearrangement of differently α,α-disubstituted a-siloxy aldehydes
Ohmatsu, Kohsuke,Tanaka, Takayuki,Ooi, Takashi,Maruoka, Keiji
supporting information; experimental part, p. 5203 - 5206 (2009/04/11)
(Chemical Equation Presented) Control of the migration tendency: The regiodivergent 1,2-rearrangement of asiloxy aldehydes bearing α-aryl and α-alkyl substituents into α-siloxy ketones has been realized by using different aluminum Lewis acid catalyst/solvent systems (see scheme). The scope of this unprecedented protocol has been investigated with various substrates and clearly demonstrates its utility for the selective synthesis of two structural isomers from one substrate.
Asymmetric dihydroxylation of disubstituted allenes
Fleming, Steven A.,Liu, Renmao,Redd, J. Ty
, p. 8095 - 8098 (2007/10/03)
Asymmetric dihydroxylation of 1,1-disubstituted and 1,3-disubstituted allenes can be used to synthesize chiral α-hydroxy ketones. We have also obtained α,α′-dihydroxy ketones with high enantioselectivity from 1,3-disubstituted allenes. Low conversion of the dihydroxylation of chiral allenes can be used as a kinetic resolution of sterically hindered allenes.
Asymmetric acyloin condensation catalysed by phenylpyruvate decarboxylase. Part 2: Substrate specificity and purification of the enzyme
Guo, Zhiwei,Goswami, Animesh,Nanduri, Venkata B.,Patel, Ramesh N.
, p. 571 - 577 (2007/10/03)
Phenylpyruvate decarboxylase from Achromobacter eurydice was used to catalyse the asymmetric acyloin condensation of phenylpyruvate 1 with various aldehydes 2 to produce optically active acyloins PhCH2COCH(OH)R 3. The specific activity of the phenylpyruvate decarboxylase enzyme was increased by a factor of 332 after its purification. The molecular weight of the purified enzyme was shown to be 150 kDa by gel filtration chromatography, while SDS gel electrophoresis showed two sub-units with molecular weights of 90 and 40 kDa. The acyloin condensation yield decreased with increasing chain length for straight chain aliphatic aldehydes from 76% for acetaldehyde to 24% for valeraldehyde. The e.e.s of the acyloin products were 87-98%. Low yields of acyloin products were obtained with chloroacetaldehyde (13%) and glycoaldehyde (16%). Indole-3-pyruvate was a substrate of the enzyme and provided acyloin condensation product 3-hydroxy-1-(3-indolyl)-2-butanone 5 with acetaldehyde in 19% yield, while benzoylformate was not a substrate for the enzyme.
Syntheses of Dialkyl and Functionalized Ketones via 1-(Benzotriazol-1-yl)alkyl Methyl Thioethers
Katritzky, Alan R.,Oniciu, Daniela C.,Ghiviriga, Ion,Soti, Ferenc
, p. 2110 - 2115 (2007/10/03)
Benzotriazol-1-ylmethyl methyl thioether (1), after easy deprotonation by BuLi, reacted with alkyl halides to afford 1-(benzotriazol-1-yl)alkyl methyl thioethers 2 in good yields. The utility of compounds 2 as alkanoyl anion equivalents was demonstrated by the reactions of their anions with alkyl halides, aldehydes, ketones, esters, and phenyl isocyanate: the products were readily hydrolyzed to α-functionalized ketones in dilute aqueous acid.
LICKOR-Promoted 1,2-elimination in 1,1-dimethoxy-2-phenylethane and 1,1-dimethoxy-2-phenylpropane: synthesis of substituted enol ethers and alkynes
Deagostino, Annamaria,Mella, Mariella,Prandi, Cristina,Venturello, Paolo
, p. 2757 - 2760 (2007/10/02)
Dimethyl acetals of phenylacetaldehyde 1a and 2-phenylpropionaldehyde 1b, upon treatment with 1.25 equiv. of LICKOR reagent, undergo 1,2-elimination (THF at -95 deg C) promoted by metallation at the benzylic site, and afford the corresponding enol ethers in the E-form.When the substrate is treated with excess of the base (2.5 equiv.), further hydrogen-metal exchange takes place at the α-vinyl site of the elimination product, and carbonyl electrophiles can be added to the carbanionic intermediate yielding allyl alcohols.Experimental procedures are given for the conversion of the α-substituted derivatives into carbonyl compounds, according to an inverse polarity approach.Moreover, allyl alcohols synthesized starting from 1a, can be transformed into prop-2-ynyl alcohols by treatment with LICKOR base.
Substituted (Carbazol-9-yl)(benzotriazol-1-yl)methanes: Novel Acyl Anion Equivalents
Katritzky, Alan R.,Yang, Zhijun,Lam, Jamshed N.
, p. 6917 - 6923 (2007/10/02)
Alkyl(carbazol-9-yl)(benzotriazol-1-yl)methanes are deprotonated by BuLi to form anions which react with alkyl halides, aldehydes, and isocyanates to afford the expected products and which add 1,4 to α,β-unsaturated ketones.These products are hydrolyzed by dilute acid at ambient temperature to afford the corresponding ketones.
