564-04-5Relevant articles and documents
Reactivity of Lithium β-Ketocarboxylates: The Role of Lithium Salts
Berton, Mateo,Mello, Rossella,Williard, Paul G.,González-Nú?ez, María Elena
supporting information, p. 17414 - 17420 (2017/12/15)
Lithium β-ketocarboxylates 1(COOLi), prepared by the reaction of lithium enolates 2(Li+) with carbon dioxide, readily undergo decarboxylative disproportionation in THF solution unless in the presence of lithium salts, in which case they are indefinitely stable at room temperature in inert atmosphere. The availability of stable THF solutions of lithium β-ketocarboxylates 1(COOLi) in the absence of carbon dioxide allowed reactions to take place with nitrogen bases and alkyl halides 3 to give α-alkyl ketones 1(R) after acidic hydrolysis. The sequence thus represents the use of carbon dioxide as a removable directing group for the selective monoalkylation of lithium enolates 2(Li+). The roles of lithium salts in preventing the disproportionation of lithium β-ketocarboxylates 1(COOLi) and in determining the course of the reaction with bases and alkyl halides 3 are discussed.
Mild N-deacylation of secondary amides by alkylation with organocerium reagents
Wang, Ai-E.,Chang, Zong,Liu, Yong-Peng,Huang, Pei-Qiang
supporting information, p. 1055 - 1058 (2015/09/01)
Secondary amides are a class of highly stable compounds serving as versatile starting materials, intermediates and directing groups (amido groups) in organic synthesis. The direct deacylation of secondary amides to release amines is an important transformation in organic synthesis. Here, we report a protocol for the deacylation of secondary amides and isolation of amines. The method is based on the activation of amides with Tf2O, followed by addition of organocerium reagents, and acidic work-up. The reaction proceeded under mild conditions and afforded the corresponding amines, isolated as their hydrochloride salts, in good yields. In combination with the C-H activation functionalization methodology, the method is applicable to the functionalization of aniline as well as conversion of carboxylic derivatives to functionalized ketones.
Synthesis of η1 Oxygen-Bound Rhodium Enolates. Applications to Catalytic Aldol Chemistry
Slough, Greg A.,Bergman, Robert G.,Heathcock, Clayton H.
, p. 938 - 949 (2007/10/02)
Oxygen-bound rhodium enolate complexes are prepared by metathesis of carbonylbis(phosphine)rhodium(I) halides and potassium enolates, 3-6.Rhodium enolates of acetophenone (7), propiophenone (9), ethyl mesityl ketone (10), and ethyl tert-butyl ketone (11) were prepared and fully characterized.Complex 11 condenses with benzaldehyde under a variety of conditions to produce isolable rhodium aldolate complex 12.Cleavage of 12 with trimethylsilyl chloride yields aldol silyl ether and rhodium chloride.Similar treatment of 12 with an enol silane affords the aldol silylether and a rhodium enolate.A catalytic aldol reaction involving enol silanes, silylketene acetals, and benzaldehyde under rhodium catalysis is presented.Deuterium, phosphorus, and carbon NMR were used to demonstrate the intermediacy of rhodium enolates and aldolates in the aldol process and to elucidate the gross mechanistic features of the catalytic cycle.
KINETICS OF THE GAS-PHASE THERMAL DECOMPOSITION OF 2,3-DIMETHYL-2,3-EPOXYPENTANE
Flowers, Michael C.,Honeyman, Malcolm R.
, p. 2179 - 2184 (2007/10/02)
In the temperature range 638-727 K 2,3-dimethyl-2,3-epoxypentane decomposes by homogeneous, unimolecular and non-radical mechanisms to give propene, propanone, but-1-ene, cis- and trans-but-1-ene, butanone, 2,2-dimethylpentan-3-one, 3,3-dimethylpentan-2-one, 2,3-dimethylpent-1-en-3-ol, 3-ethyl-2-methylbut-3-en-2-ol and 2,3-dimethylpent-3-en-2-ol as the major products.These products arise as the consequence of seven competing primary processes and the Arrhenius parameters for each of these processes are determined.The results and conclusions of this study are in accord with those of previous studies of the thermal decompositions of other alkyl-substituted oxiranes.
Untersuchungen zur Kinetik und zum Mechanismus der Isooctanoxydation
Lischke, G.,Oehlmann, G.
, p. 555 - 572 (2007/10/02)
Isooctan wurde mit Sauerstoff in einem statischen Reaktor aus Rasothermglas im Temperaturbereich zwischen 538 K und 593 K oxydiert.Aus kinetischen Untersuchungen folgt fuer den Bereich der stationaeren Reaktionsgeschwindigkeit ein Zeitgesetz rstat = k32.Die scheinbare Aktivierungsenergie betraegt: EA = 220 +/- 3 kJ/mol.Als charakteristische Reaktionsprodukte wurden 2,2,4,4-Tetramethyltetrahydrofuran, 2-tert.-Butyl-3-methyl-oxetan, α-Diisobuten, β-Diisobuten, β-Diisobutenoxid, Isooktanon sowie 2,2-Dimethylpentanon-3 und -4 gefunden.Aus der Verschiedenartigkeit der Produkte der Isooctanoxydation zu denen der Diisobutenoxydation folgt, dass bei der Alkanoxydation das strukturanaloge Olefin parallel mit anderen sauerstoffhaltigen Produkten gebildet wird.Isootylhydroperoxide koennen unter den Reaktionsprodukten nicht nachgewiesen werden.Durch das Fehlen C-zahlgleicher Hydroperoxide unterscheidet sich iso-Octan hinsichtlich seines Oxydationsverhaltens in charakteristischer Weise von unverzweigten Kohlenwasserstoffen (z.B. n-Heptan).Ein Reactionsmechanismus wird vorgeschlagen.
