- Hydroperoxidations of Alkenes using Cobalt Picolinate Catalysts
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Hydroperoxides were synthesized in one step from various alkenes using Co(pic)2as the catalyst with molecular oxygen and tetramethyldisiloxane (TMDSO). The hydration product could be obtained using a modified catalyst, Co(3-mepic)2, with molecular oxygen and phenylsilane. Formation of hydroperoxides occurred through a rapid Co-O bond metathesis of a peroxycobalt compound with isopropanol.
- Peralta-Neel, Zulema,Woerpel
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supporting information
p. 5002 - 5006
(2021/06/30)
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- SPIRO-OXAZOLONES
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The present invention provides spiro-oxazolones, which act as V1a receptor modulators, and in particular as V1a receptor antagonists, their manufacture, pharmaceutical compositions containing them and their use as medicaments. The present compounds are useful as therapeutics acting peripherally and centrally in the conditions of inappropriate secretion of vasopressin, anxiety, depressive disorders, obsessive compulsive disorder, autistic spectrum disorders, schizophrenia, aggressive behavior and phase shift sleep disorders, in particular jetlag.
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Page/Page column 79; 80
(2015/09/28)
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- Manganese(IV)-mediated hydroperoxyarylation of alkenes with aryl hydrazines and dioxygen from air
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We report a new carbooxygenation-type version of the Meerwein arylation in which the introduction of oxygen is achieved by using dioxygen from the air. In this way, hydroperoxides were obtained from activated as well as non-activated alkenes by oxidizing aryl hydrazines with manganese dioxide. The best results were obtained with α-substituted acrylates. Importantly, the aryl hydrazine has to be added slowly to the reaction mixture to allow sufficient uptake of dioxygen from the air. Competition and labeling experiments revealed hydroperoxyl radicals as novel oxygen-centered radical scavengers. The introduction of oxygen into a Meerwein arylation has been achieved with dioxygen from air as an oxygen-centered radical scavenger. The slow addition of the aryl hydrazine is key to aryl radical formation through oxidation with manganese dioxide; whereby, hydroperoxides were obtained from activated as well as non-activated alkenes.
- Kindt, Stephanie,Jasch, Hannelore,Heinrich, Markus R.
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p. 6251 - 6255
(2014/06/09)
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- A mild oxidative aryl radical addition into alkenes by aerobic oxidation of arylhydrazines
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A mild and practical oxyarylation of alkenes by oxidative radical addition has been developed by using aerobic oxidation of hydrazine compounds. The use of a catalytic amount of potassium ferrocyanide trihydrate (K4[Fe(CN) 6]·3 H2O) and water accelerated this radical reaction to give peroxides or alcohols from simple alkenes in good yields. The environmentally friendly and economical radical reactions were achieved at room temperature in the presence of iron catalyst, oxygen gas, and water. A method involving aniline as a radical precursor is also described. Copyright
- Taniguchi, Tsuyoshi,Zaimoku, Hisaaki,Ishibashi, Hiroyuki
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p. 4307 - 4312
(2011/05/07)
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- Stereospecific decarboxylative allylation of sulfones
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Allyl sulfonylacetic esters undergo highly stereospecific, palladium-catalyzed decarboxylative allylation. The reaction allows the stereospecific formation of tertiary homoallylic sulfones in high yield. In contrast to related reactions that proceed at -100 °C and require highly basic preformed organometallics, the decarboxylative coupling described herein occurs under mild nonbasic conditions and requires no stoichiometric additives. Allylation of the intermediate α-sulfonyl anion is more rapid than racemization, leading to a highly enantiospecific process. Density functional theory calculations indicate that the barrier for racemization is 9.9 kcal/mol, so the barrier for allylation must be 9.9 kcal/mol.
- Weaver, Jimmie D.,Ka, Being J.,Morris, David K.,Thompson, Ward,Tunge, Jon A.
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supporting information; scheme or table
p. 12179 - 12181
(2010/10/03)
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- Synthesis of chiral nonracemic tertiary α-thio and α-sulfonyl acetic esters via SN2 reactions of tertiary mesylates
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Syntheses of enantioenriched sulfides and sulfones via substitution of tertiary mesylate with thiolate nucleophile were achieved with modest to excellent success. Georg Thieme Verlag Stuttgart New York.
- Weaver, Jimmie D.,Morris, David K.,Tunge, Jon A.
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scheme or table
p. 470 - 474
(2010/04/29)
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- Mitsunobu approach to the synthesis of optically active α,α-disubstituted amino acids
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Chiral tertiary α-hydroxy esters of known stereochemical configuration were transformed to α-azido esters by Mitsunobu reaction with HN3. Optimization of this reaction was shown to proceed at room temperature with high chemical yield using 1,1-(azodicarbonyl)dipiperidine (ADDP) and trimethylphosphine (PMe3). Complete inversion of configuration was observed at the α-carbon. Several α,α- disubstituted amino acids were synthesized in high overall chemical yield and optical purity.
- Green, Jonathan E.,Bender, David M.,Jackson, Stona,O'donnell, Martin J.,Mccarthy, James R.
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supporting information; experimental part
p. 807 - 810
(2009/08/08)
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- Manganese-promoted regioselective ring-opening of 2,3-epoxy acid derivatives: a new route to α-hydroxy acid derivatives
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A simple and general methodology directed towards the synthesis 3-aryl-2-hydroxy amides, or esters with total regioselectivity from the easily available 2,3-epoxy amides or esters, promoted by active manganese is described. Utilizing enantiopure epoxy amides as starting materials, the corresponding 3-aryl-2-hydroxy amides in enantiopure form are also available. Some synthetic applications of selected examples of 3-aryl-2-hydroxy carboxylic acid derivatives are shown. A mechanism has been proposed to explain this novel reaction.
- Concellon, Jose M.,Bernad, Pablo L.,Rodriguez-Solla, Humberto,Diaz, Pamela
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experimental part
p. 2178 - 2184
(2009/12/31)
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- Stereoselective synthesis of Z-α-aryl-α,β-unsaturated esters
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An efficient method for the stereoselective synthesis of (Z)-α-arylacrylates is described. Treatment of α-hydroxyesters with triflic anhydride and pyridine at 0 °C followed by warming to room temperature afforded the corresponding (Z)-α-aryl-α,β- unsatura
- Mani, Neelakandha S.,Mapes, Christopher M.,Wu, Jiejun,Deng, Xiaohu,Jones, Todd K.
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p. 5039 - 5042
(2007/10/03)
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- Catalytic asymmetric epoxidation of α-methyl α,β- unsaturated anilides as ester surrogates
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Catalytic asymmetric epoxidation of α-methyl α,β- unsaturated carboxylic acid derivatives was achieved using anilide as a template. The Pr(Oi-Pr)3-6,6?-Ph-BINOL complex (10 mol%) with a Ph3P(O) (30 mol%) additive promoted the epoxida
- Chen, Zhihua,Morimoto, Hiroyuki,Matsunaga, Shigeki,Shibasaki, Masakatsu
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p. 3529 - 3532
(2007/10/03)
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- Enantioselective synthesis of eucomols using sharpless catalytic asymmetric dihydroxylation
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A novel synthetic method was developed for eucomols, (S)-3-hydroxyhomoisoflavanones. Addition of aryllithium to aldehyde ((S)-9) obtained by asymmetric dihydroxylation of 4, followed by the formation of cyclic ether, gave eucomols, (S)-3-hydroxyhomoisofla
- Jew, Sang-Sup,Kim, Hyun-Ah,Kim, Jeong-Hoon,Park, Hyeung-Geun
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