Synthesis of the C-1−C-28 ABCD Unit of Spongistatin 1

Gaunt, Matthew J.; Jessiman, Alan S.; Orsini, Paolo; Tanner, Huw R.; Hook, David; Ley, Steven V.

doi:10.1021/ol035849+

Cited by 92 publications

(62 citation statements)

References 11 publications

(16 reference statements)

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“…This technique, first introduced by Ley et al in 2001 (see Section 2.9.4), [51] is becoming increasingly popular, as demonstrated by the many recently published examples. [52][53][54][55][56][57][58][59][60] Systematic studies on temperature profiles and the thermal stability of ionic liquids under microwave irradiation conditions by Leadbeater and Torenius [52,53] have shown that addition of a small amount of an ionic liquid (0.1 mmol mL À1 solvent) suffices to obtain dramatic changes in the heating profiles by changing the overall dielectric properties (namely, tand) of the reaction medium.…”

Section: Heck Reactionsmentioning

confidence: 99%

“…[137] Here it was essential to use openvessel technology, since the two equivalents of the volatile byproduct ethanol that formed under normal (atmospheric pressure) conditions were simply distilled off and therefore Scheme 19. Petasis olefination, [60] hydrosilylation of ketones, [134] and Dötz benzannulation. [135] CAN = cerium ammonium nitrate, TBS = tertbutyldimethylsilyl, TES = triethylsilyl, TIPS = triisopropylsilyl.…”

Section: Heterocycle Synthesismentioning

confidence: 99%

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Controlled Microwave Heating in Modern Organic Synthesis

2004

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Although fire is now rarely used in synthetic chemistry, it was not until Robert Bunsen invented the burner in 1855 that the energy from this heat source could be applied to a reaction vessel in a focused manner. The Bunsen burner was later superseded by the isomantle, oil bath, or hot plate as a source for applying heat to a chemical reaction. In the past few years, heating and driving chemical reactions by microwave energy has been an increasingly popular theme in the scientific community. This nonclassical heating technique is slowly moving from a laboratory curiosity to an established technique that is heavily used in both academia and industry. The efficiency of “microwave flash heating” in dramatically reducing reaction times (from days and hours to minutes and seconds) is just one of the many advantages. This Review highlights recent applications of controlled microwave heating in modern organic synthesis, and discusses some of the underlying phenomena and issues involved.

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Section: Heck Reactionsmentioning

confidence: 99%

Section: Heterocycle Synthesismentioning

confidence: 99%

Controlled Microwave Heating in Modern Organic Synthesis

2004

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“…Their basic mono-or bis-spiroketal framework resembles that found in many relevant natural products, including steroidal saponins, polyether ionophores, macrolide antibiotics, insect pheromones, and toxic metabolites from algae and fungi [1][2][3][4][5], and is the target of much synthetic effort [6][7][8][9][10][11][12][13][14]. DFAs are formed upon thermal and/or acidic activation of sucrose-and/or D-fructose-rich materials.…”

Section: Introductionmentioning

confidence: 99%

Chemical and Enzymatic Approaches to Carbohydrate-Derived Spiroketals: Di-D-Fructose Dianhydrides (DFAs)

et al. 2008

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Di-D-fructose dianhydrides (DFAs) comprise a unique family of stereoisomeric spiro-tricyclic disaccharides formed upon thermal and/or acidic activation of sucroseand/or D-fructose-rich materials. The recent discovery of the presence of DFAs in food products and their remarkable nutritional features has attracted considerable interest from the food industry. DFAs behave as low-caloric sweeteners and have proven to exert beneficial prebiotic nutritional functions, favouring the growth of Bifidobacterium spp. In the era of functional foods, investigation of the beneficial properties of DFAs has become an important issue. However, the complexity of the DFA mixtures formed during caramelization or roasting of carbohydrates by traditional procedures (up to 14 diastereomeric spiroketal cores) makes evaluation of their individual properties a difficult challenge. Great effort has gone into the development of efficient procedures to obtain DFAs in pure form at laboratory and industrial scale. This paper is devoted to review the recent advances in the stereoselective synthesis of DFAs by means of chemical and enzymatic approaches, their scope, limitations, and complementarities.

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“…Die Synthese von Fragment 4 startete mit einer WittigOlefinierung von Aldehyd 6 [11,12] und dem Entschützen im Sauren. [13] Der Alkohol 10 wurde mit Dess-Martin-Periodinan oxidiert und durch Wittig-Reaktion mit dem stabilisierten Ylid 11 zum Ester 12 olefiniert (Schema 3).…”

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