6790-20-1Relevant articles and documents
Synthesis of α-oxygenated ketones and substituted catechols via the rearrangement of N-enoxy- and N-aryloxyphthalimides
Kroc, Michelle A.,Patil, Aditi,Carlos, Anthony,Ballantine, Josiah,Aguilar, Stephanie,Mo, Dong-Liang,Wang, Heng-Yen,Mueller, Daniel S.,Wink, Donald J.,Anderson, Laura L.
, p. 4125 - 4137 (2017/06/29)
A common approach to the synthesis of α-oxygenated carbonyl compounds and catechols is the treatment of a carbonyl compound or a phenol with an electrophilic oxygen source. As an alternative approach to these important structures, formal [3,3]-rearrangements of N-enoxyphthalimides, N-enoxyisoindolinones, and N-aryloxyphthalimides have been explored. When used in combination with an initial Chan-Lam coupling, these transformations facilitate the dioxygenation of alkenylboronic acids for the synthesis of α-oxygenated ketones and the dioxygenation of arylboronic acids for the synthesis of catechols. The rearrangements of N-enoxyisoindolinones have also been shown to be diastereoselective.
Preparation of α-oxygenated ketones by the dioxygenation of alkenyl boronic acids
Patil, Aditi S.,Mo, Dong-Liang,Wang, Heng-Yen,Mueller, Daniel S.,Anderson, Laura L.
, p. 7799 - 7803 (2012/09/08)
Two in two: Dioxygenation of alkenyl boronic acids has been achieved with N-hydroxyphthalimide. The two-step process involves etherification of an alkenyl boronic acid with N-hydroxyphthalimide followed by a [3,3] rearrangement. The dioxygenated product can then be hydrolyzed to form either the corresponding α-hydroxy ketone or the α-benzoyloxy ketone. Copyright
BIOFUEL PRODUCTION
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, (2009/06/27)
Methods, enzymes, recombinant microorganism, and microbial systems are provided for converting polysaccharides, such as those derived from biomass, into suitable monosaccharides or oligosaccharides, as well as for converting suitable monosaccharides or oligosaccharides into commodity chemicals, such as biofuels. Commodity chemicals produced by the methods described herein are also provided. Commodity chemical enriched, refinery-produced petroleum products are also provided, as well as methods for producing the same.
ROMPgel-supported thiazolium iodide: An efficient supported organic catalyst for parallel stetter reactions
Barrett, Anthony G. M.,Love, Andrew C.,Tedeschi, Livio
, p. 3377 - 3380 (2007/10/03)
(Chemical Equation Presented) A high-loading ROMPgel-supported thiazolium iodide was prepared via ROMPolymerization of the corresponding norbornene-derived monomer. The resulting ionic ROMPgel proved to be an efficient organic catalyst for Stetter reactions. The 1,4-dicarbonyl products, important intermediates in the synthesis of cyclopentenones and heterocycles, were obtained in high yields and excellent purities after minimal purification. The ROMPgel could be reused in up to four consecutive reaction cycles without significant loss of catalytic activity.
Oxidation of alcohols with nitroxyl radical under polymer-supported two-phase conditions
Yoshitomo, Kashiwagi,Chiba, Shinya,Anzai, Jun-ichi
, p. 1545 - 1549 (2007/10/03)
The oxidation of alcohols to carbonyl compounds was studied using potassium hexacyanoferrate(III) mediated by nitroxyl radical as the catalyst under polymer-supported organic-aqueous two-phase conditions. Primary alcohols are readily oxidized to the corresponding aldehydes in excellent yield with no over-oxidation to carboxylic acids. Secondary alcohols are converted to the corresponding ketones with a much lower efficiency. The oxidation reactions of primary alcohols in the presence of secondary alcohols is strongly favored. Primary-secondary diols are selectively transformed into hydroxy aldehydes with small amounts of ketoaldehydes, the amount of isomeric keto alcohols remaining is less than 1%.
New coupling reactions of some acyl chlorides with samarium diiodide in the presence of samarium: Carbinols from three acyl units
Clausen, Christian,Weidner, Ingo,Butenschoen, Holger
, p. 3799 - 3806 (2007/10/03)
A mixture of samarium(II) iodide and samarium can induce a coupling reaction of three molecules of alkanoyl halide to give trialkylcarbinols of 2-hydroxy-1,3-diones. When aliphatic, unbranched alkanoyl chlorides are used, this new coupling reaction provides trimeric products as the main reaction products. Tetrahydropyran (THP) proved superior as the solvent because no ring-opening and subsequent reaction with the alkanoyl halides was observed under the reaction conditions, unlike when THF was used. Wiley-VCH Verlag GmbH, 2000.
The reduction of α-silyloxy ketones using phenyldimethylsilyllithium
Fleming, Ian,Roberts, Richard S.,Smith, Stephen C.
, p. 1215 - 1228 (2007/10/03)
Phenyldimethylsilyllithium reacts with acyloin silyl ethers RCH(OSiMe3)COR 8 to give regiodefined silyl enol ethers RCH=C(OSiMe2Ph)R 9, and hence by hydrolysis ketones RCH2COR 10. The yields can be high but are usually moderate. The mechanism of this reduction is established to involve a Brook rearrangement (Scheme 6) rather than a Peterson elimination (Scheme 1). Although the mechanism appears to be the same in each case, the stereochemistries of the silyl enol ethers 9 are opposite in sense in the aromatic series (R = Ph, Scheme 7) and the aliphatic series (R = cyclohexyl, Scheme 8), with the major aromatic silyl enol ether being the thermodynamically less stable isomer E-PhCH=C(OSiMe2Ph)Ph E-9aa, and the major aliphatic silyl enol ether being the thermodynamically more stable isomer Z-c-C6H11CH= C(OSiMe2Ph)-c-C6H11 Z-9ba. This is a consequence of anomalous anti-Felkin attack in the aromatic series. The reaction with the silyl ether ButCH(OSiMe3)COPh 13b is normal in giving Z-ButCH= C(OSiMe2Ph)Ph Z-38 (Scheme 11), but reduction of the silyl ether 8a with lithium aluminium hydride is also anti-Felkin giving with high selectivity the meso diol PhCH(OH)CH(OH)Ph 39. The reaction between Phenyldimethylsilyllithium and the acyloin silyl ether 8d (R = But) does not give the ketone ButCH2COBut, but gives instead the anti-Felkin meso diol ButCHOHCHOHBut 40 also with high selectivity (Scheme 12). Silyllithium and some related reagents react with trifluoromethyl ketones 46 and 48 to give α,α-difluoro silyl enol ethers 47 and 49 (Scheme 14).
Convenient Preparation of 'High-Surface Sodium' in Liquid Ammonia: Use in the Acyloin Reaction
Makosza, Mieczyslaw,Grela, Karol
, p. 267 - 268 (2007/10/03)
'Sodium on solid support' (5-20 wt.% of Na on NaCl, glass powder, poly(ethylene) and poly(propylene)) can be conveniently prepared via low-temperature (-33°C) deposition of sodium from its solution in liquid ammonia. Use of this reagent in the acyloin reaction of carboxylic esters gave the corresponding products in good yields.
Catalytic action of azolium salts. VI. Preparation of benzoins and acyloins by condensation of aldehydes catalyzed by azolium salts
Miyashita,Suzuki,Iwamoto,Higashino
, p. 2633 - 2635 (2007/10/02)
Benzoins 4 (2-hydroxyethanones substituted with aryl groups at the 1- and 2-positions) were prepared by self-condensation of aromatic aldehydes 3 using catalytic amounts of azolium salts 1 and 2 in excellent yields. 1,3-Dimethylbenzimidazolium iodide (2) was an effective catalyst for the preparation of acyloins 6 (2-hydroxyethanones substituted with alkyl groups at the 1- and 2-positions) by self-condensation of aliphatic aldehydes 5. On the other hand, an attempt at the condensation of hexanal (5d) catalyzed by 1,3-dimethylimidazolium iodide (1) failed to yield the acyloin 6d, and instead the aldol-type condensed product 8d was obtained.
The acyloin reaction using tethered diesters
Daynard, Tim S.,Eby, Paul S.,Hutchinson, John H.
, p. 1022 - 1028 (2007/10/02)
A study of the intramolecular acyloin condensation using diesters tethered by their alkoxide groups was undertaken.The goal was to provide a method for optimizing the yield of mixed acyloin products from the reaction of two different esters by utilizing tethered dissimilar esters as substrates.The results of the study show that the yield of the acyloin condensation is dependant on the tether length.Tethers of 8 and 14 carbons in length give yields comparable to those obtained from an intermolecular control reaction while shorter tethers give reduced yields of product.However, the use of mixed tethered diesters and a crossover experiment between two different tethered substrates provides a statistical distribution of products.These observations have been interpreted as resulting from a fragmentation of the initially formed radical anion intermediate that destroys the tethered nature of the substrate(s).
