Trans Dialkoxylation of Cyclic Alkenes: A Prévost-Type Reaction

Schauble, J. Herman; Trauffer, Edward A.; Deshpande, Prashant P.; Evans, Robert D.

doi:10.1055/s-2005-865333

Cited by 28 publications

(10 citation statements)

References 8 publications

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“…Neither unreacted alkene nor the intermediated iodohydrin were detected. As it is well-known that Ag(I) salts can assist solvolysis of alkyl halide, 21 the coiodination of alkenes mediated by Bentonit-Ag clay was tested. Using this procedure, the iodohydrins were efficiently obtained, but only traces of epoxides were formed.…”

Section: Resultsmentioning

confidence: 99%

A new environmental friendly clay catalyst for one-pot coiodination and epoxidation of alkenes

Bernini

Aguiar

2007

J. Braz. Chem. Soc.

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A argila comercial brasileira Bentonit Brasgel ® foi caracterizada por análises química e textural, DRX e RMN no estado sólido de 27 Al and 29 Si, que indicaram a presença de quartzo-α e esmectita como argilo-minerais. Essa argila se mostrou um catalisador eficiente para a conversão de alquenos nos respectivos epóxidos através da reação com iodo/água seguida de adição de KOH em hexano in situ (80-91 %). Resultados similares foram obtidos usando-se Bentonit Brasgel™ intercalada com Ag(I).The commercial Brazilian clay Bentonit Brasgel™ was characterized by chemical and textural analyses, XRD, and 27 Al and 29 Si MAS-NMR, that indicated the presence of α-quartz and smectite as clay-minerals. This natural clay proved to be an efficient catalyst for the conversion of alkenes into epoxides by the reaction with iodine/water followed by in situ addition of KOH in hexane (80-91 % yield). Similar results were obtained with Bentonit Brasgel™ intercalated with Ag(I). Keywords: epoxide, coiodination, iodohydrin, clay, alkenes IntroductionNowadays, the search for cleaner process is one of the major challenges in modern chemical industries. 1 Moreover, the high versatility, low-cost and gain in yield/ selectivity turn clays very attractive catalysts in the green chemistry point of view as they are reusable and present minimal environmental impact. 2 Within this context, the use of clays and clay-minerals in synthetic organic chemistry has increased enormously in the last years. 3 Epoxides are useful compounds in synthetic organic chemistry 3 and the interest for these valuable compounds has increased with the discovery of some biological activities related to the oxirane ring. 5 There are several efficient methodologies for the preparation of epoxides, for example: the oxidation of alkenes with peracids and the cyclization of halohydrins with bases are the most employed. 4 Peracids and analogues have been used to prepare epoxides; even though, these reagents must be carefully manipulated, due to their tendency to explosion. 6 The epoxidation of alkenes with molecular O 2 or H 2 O 2 seems to be very attractive, but it is expensive because it needs a metal-based catalytic system 7 or zeolites 8 and frequently suffers from formation of undesirable oxygenated by-products. Metal-free epoxidation of alkenes with H 2 O 2 occurs in the presence of some auxiliaries (nitriles, carbodiimides, etc) which convert hydrogen peroxide to a more active oxidant. 9 On the other hand, halohydrins are widely used in epoxide synthesis in both laboratorial and industrial scale. 10 The cohalogenation 11 with water (halogenation of alkenes in aqueous solutions) is an effective way to prepare these intermediates. 12 Although this methodology is effective, the handling and manipulation of toxic and corrosive halogens is problematic (especially in large-scale), then the search for alternative sources of electrophilic halogen is of great interest. 13 1510A New Environmentally Friendly Clay Catalyst for One-pot Coiodination J. Braz. Chem. Soc.Recently, we...

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Section: Resultsmentioning

confidence: 99%

A new environmental friendly clay catalyst for one-pot coiodination and epoxidation of alkenes

Bernini

Aguiar

2007

J. Braz. Chem. Soc.

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“…Furthermore, Schauble et al. successfully utilized a variety of alcohols as nucleophiles in the Ag salt/I 2 ‐mediated anti ‐dialkoxylation of cyclic alkenes to furnish the trans ‐bisethers 40 as products in moderate to good yields (Scheme ) . The reaction occurs with the Ag‐assisted formation of an iodonium 37 , followed by ring‐opening reaction with alcohol to give a trans ‐iodoether 38 , which subsequently undergoes iodide abstraction to form the oxiranium ion 39 .…”

Section: Anti‐dioxygenation With Cyclic Cationic Intermediatesmentioning

confidence: 99%

Vicinal anti‐Dioxygenation of Alkenes

Wang

2018

Asian J Org Chem

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Vicinal diols and their derivatives are common motifs in al arge number of biologically active compounds and are also important intermediates in organics ynthesis. To achieve these structural units in ah ighly stereoselective manner,d irect dioxygenation of simple alkene precursors has provedt ob et he most straightforward approach, and thus many practical proceduresu sing various strategies have been developed. In this Focus Review ac oncise summary of the main methods for anti-dioxygenation of olefins is presented. Scheme1.Categories of vicinal anti-dioxygenation of alkenes.[a] Prof.Scheme6.Ammonium-directed formal anti-dioxygenation as key step for the synthesis of aza-and amino sugars.Scheme7.N-Oxide-directed formal anti-dihydroxylation.Scheme8.NafionN R50-catalyzed anti-dihydroxylation.Scheme9.PTSA-catalyzed anti-dihydroxylation.Scheme14. SeO 2 -catalyzed anti-dihydroxylation.Scheme15. Diselenide-catalyzed anti-dihydroxylationo fcyclohexene.Scheme16. Chiral-diselenide-catalyzed asymmetric anti-dihydroxylation.

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“…However this reaction suffers from the harsh conditions, high raction times and frequently low yields Aryl substituted 3,4-dihydropyrimidine-2-(1H)-ones 3 and their derivatives are an important class of substances in organic and medicinal chemistry. Many synthetic methods [4][5][6][7][8] for preparing these compounds have been reported including classical methods, microwave irradiation and by using Lewis acids as well as protic acids. The discovery of a new an inexpensive catalyst for the preparation of 3,4-dihydropyrimidine-2-(1H)-ones under neutral and mild conditions with high yield of prime importance.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Chemical Synthesis of Pyrimidine Derivatives by Using Grindstone Chemistry Technique and Conventional Method

Sonawane

2014

ILCPA

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The majority of the drugs on the market today are entirely chemically synthesized in the laboratory. Several scientists had synthesized dihydropyrimidine (DHPMs) derivatives showing a wide spectrum of biological actions as antibacterials, antivirals as well as antitumor agents. This activity is principally due to presence of steriogenic carbon C4 in their structure. The current investigation is comparative study of chemically synthesis of two DHPMs derivatives by Biginelli Reaction using conventional method and grindstone chemistry technique. The synthesis of DHPMs derivative involves a multicomponent reaction (aldehyde derivative, urea /thiourea and 1,3-dicarbonyl compounds) in presence of HCl / NH 4 Cl as a catalyst. Two derivative viz. 3,4-dihydropyrimidin-2-(1H)-ones and 3,4-dihydropyrimidin-2-(1H)-thiones were synthesized and characterized using IR. The melting points were obtained are 208 °C and 210 °C respectively. "Grindstone Chemistry Technique" catalyzed by CuCl 2 ·2H 2 O and Conc. HCl. gave more yield, solvent free and ecofriendly. The obtained products have been identified by comparison with spectral data & their melting points. This study will help to develop easy protocol for the synthesis of many more DHPMs derivative with high yield.

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Trans Dialkoxylation of Cyclic Alkenes: A Prévost-Type Reaction

Cited by 28 publications

References 8 publications

A new environmental friendly clay catalyst for one-pot coiodination and epoxidation of alkenes

A new environmental friendly clay catalyst for one-pot coiodination and epoxidation of alkenes

Vicinal anti‐Dioxygenation of Alkenes

Comparative Study of Chemical Synthesis of Pyrimidine Derivatives by Using Grindstone Chemistry Technique and Conventional Method

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