- New synthetic methodology for ring expansion of n-sized conjugated cycloalkenones into homoallylic n+3 lactones: Three-step synthesis of fragrant phoracantholide
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Under the influence of Lewis acidic boron trifluoride-diethyl etherate, epoxides are activated sufficiently to undergo rapid nucleophilic opening by ketone enolate ions at -78°C, forming useful γ-lactols. Application of this protocol to n+3 ring expansion features one-flask, multicomponent, sequential reactions. (C) 2000 Elsevier Science Ltd.
- Posner,Wang,Halford,Elias,Maxwell
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Read Online
- Direct synthesis of keto nitroaliphatics via retro-Henry reaction of cyclic 2-nitroalcohols by anhydrous copper sulfate adsorbed on silica gel. A short synthesis of (±)-phoracantholide I
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It has been observed that anhydrous CuSO4 adsorbed on silica gel effects the C-C bond cleavage between the hydroxy group and the nitro group of 2-nitroalcohols. In the case of 2-nitrocyclohexanols, the products are RCO(CH2)4/su
- Saikia, Anil K.,Hazarika, Monoj J.,Barua, Nabin C.,Bezbarua, Maitreyee Sarma,Sharma, Ram P.,Ghosh, Anil C.
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Read Online
- Stereoselective synthesis of (R)-(?) and (S)-(+)-phoracantholide I from (R)-(+)-γ-valerolactone
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A concise total synthesis of (R)-(?)-phoracantholide I 1 and (S)-(+)-phoracantholide I 2 has been developed from (R)-(+)-γ-valerolactone 6. The key steps in the synthesis of these macrolides involved enzymatic reduction of Levulinic ester 4 by asymmetric dehydrogenase, Z-selective Wittig reaction of (4-carboxybutyl)triphenylphosphonium ylide 11 with lactol 7, and cyclization of seco-acid 8 using either a Yamaguchi lactonization protocol or a Mitsunobu protocol to afford (R)-(?)-phoracantholide I and (S)-(+)-phoracantholide I respectively.
- Datrika, Rajender,Kallam, Srinivasa Reddy,Khobare, Sandip R.,Gajare, Vikas S.,Kommi, Muralikrishna,Rama Mohan,Siddaiah, Vidavalur,Pratap
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p. 603 - 607
(2016/07/11)
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- Removable Silyl Group as a "masked Proton" in Oxy-2-oxonia(azonia)-Cope Rearrangement: Applications in Stereoselective Total Synthesis of Natural Macrolides
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In the presence of a Lewis acid, trimethylsilyl-substituted β,γ-unsaturated ketones and aldehydes (imines) undergo nucleophilic addition to produce zwitterionic intermediates, followed by oxy-2-oxonia(azonia)-Cope rearrangements to give homoallylic esters (amides). In the case of TMS-containing 2-vinylcycloalkanones, the process results in ring-enlargement, providing 10- to 16-membered lactones. This protocol was applied to the total synthesis of (R)-phoracantholide I.
- Mu, Wenbo,Zou, Yue,Zhou, Lijun,Wang, Quanrui,Goeke, Andreas
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p. 4982 - 4989
(2015/08/03)
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- Silver carboxylate promoted lactonization: A general method applicable to prepare medium and large-sized lactones without high dilution or slow addition
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Efficient and applicable approach to macrolactonizations, with ready availability of starting materials and simple operation, remains a challenging task for the organic community. We developed a 'freshman-can-do' protocol to medium- and large-sized lactones, not depending on high-dilution or slow addition techniques. Application of this method for the synthesis of natural lactones or potentially pharmaceutical compounds might be useful for organic chemists and pharmacists.
- Liu, Le,Xu, Shimin,Zhou, Hongwei
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p. 8386 - 8391
(2013/09/02)
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- Volatile amphibian pheromones: Macrolides from mantellid frogs from madagascar
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Amphibians like water, but do they also notice volatile compounds in the air? Yes, they do. Macrolides, such as phoracantholide-J (see picture; upper right structure) or the newly discovered natural product gephyromantolide-A (left structure), are used for communication by mantelline frogs from Madagascar. Copyright
- Poth, Dennis,Wollenberg, Katharina C.,Vences, Miguel,Schulz, Stefan
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supporting information; experimental part
p. 2187 - 2190
(2012/04/10)
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- Lipase-mediated enantioselective acylation of alcohols with functionalized vinyl esters: acyl donor tolerance and applications
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Enzymatic acylation is commonly used for the kinetic resolution of alcohols and amines. The simple acyl group introduced during the enzymatic reaction is usually removed or replaced by another group. Retention of more complex acyl moieties as part of the target structures would be a more efficient strategy. We have studied the enantioselective acylation of a model alcohol substrate, 1-phenylethanol, with vinyl esters bearing various functionality on the acyl moieties in the presence of three lipases (Candida antarctica, Candida rugosa and Burkholderia cepacia) frequently used in organic synthesis. C. antarctica lipase is the most versatile lipase for this type of biotransformations. We applied this strategy to the synthesis of a protein kinase C ligand and a natural product, phoracantholide.
- Chenevert, Robert,Pelchat, Nicholas,Morin, Pierre
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experimental part
p. 1191 - 1196
(2009/09/27)
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- New silicon-mediated ring expansion of n-sized conjugated cycloalkenones into homoallylic n+3 lactones
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Silicon nucleophilic β-addition to various 2-cycloalkenones, followed ultimately by mild and rapid α-alkylation of the corresponding cycloalkanone enolates using diverse epoxides and BF3·OEt2, produces useful γ-lactols and γ-hydroxyketones. Hypervalent iodine-promoted oxidative fragmentation then yields regiospecifically unsaturated, 3-atom ring expanded, 8-10 membered homoallylic lactones with good control of alkene geometry.
- Hatcher, Mark A.,Borstnik, Kristina,Posner, Gary H.
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p. 5407 - 5409
(2007/10/03)
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- Catalytic enantioselective synthesis of macrolides via asymmetric alkylation
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Catalytic enantioselective syntheses of the macrolides (R)-(-) phoracantholide and (R)-(+) lasiodiplodin have been achieved. Stereochemistry was introduced in using an arene chromium tricarbonyl derived catalyst, which mediated the enantioselective additi
- Jones, Graham B.,Huber, Robert S.,Chapman, Brant J.
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p. 1797 - 1809
(2007/10/03)
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- Nature-like odorants by stereoselective ring enlargement of cyclohexanone and cyclododecanone
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Both enantiomers of muscolide (3a/b), (R)-(-)-phoracantholide I [(R)-3c] and the homologous (9R)-(-)-9-tetradecanolide [(R)-3d) were synthesized by ring enlargement of cyclohexanone (6c) and cyclododecanone (6a). The ring-enlargement sequence was improved by oxidation of 9/10 with ruthenium tetroxide and reduction of 8 using catecholborane.
- Bollbuck, Birgit,Kraft, Philip,Tochtermann, Werner
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p. 4581 - 4592
(2007/10/03)
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- A Convenient Enantioselective Synthesis of (R)-(-)-Phoracantholide I, a Component of the Defensive Secretion of the Eucalypt Longicorn Phoracantha synonyma
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A short enantioselective synthesis of phoracantholide I (ee = 91percent), a component of the defensive secretion of the eucalypt longicorn Phoracantha synonyma, is described.Key steps of the synthesis are the enantioselective α-alkylation of cyclononanone SAMP hydrazone (de > 93percent) and subsequent Baeyer-Villiger reaction of the ketone (R)-3 with retention of configuration. - Key Words: Phoracantholide I, enantioselective synthesis / SAMP hydrazone / Baeyer-Villiger reaction / Defensive secretion, component of
- Enders, Dieter,Plant, Andrew,Drechsel, Karin,Prokopenko, Oleg F.
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p. 1127 - 1128
(2007/10/02)
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- Insect pheromone synthesis using Mn-salen catalyzed asymmetric epoxidation as a key step
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Enantioselective synthesis of three insect pheromones, (5Z, 13S)-5-tetradecen-13-olide, (9R)-decan-9-olide, and (S)-2-acetoxytridecane, has been achieved by using Mn-salen catalyzed asymmetric epoxidation as a key step.
- Hamada,Daikai,Irie,Katsuki
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p. 2441 - 2451
(2007/10/03)
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- A New Synthesis of (+/-)-Phoracantholide, (+/-)-Dihydrorecifeiolide, and (+/-)-Muscone via α-Nitro Ketones
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Cα' alkylation of α-nitro cycloalkanones 1a-c with methyl iodide at -35 to -70 deg C in THF/heptane/DMPU/TMDA in the presence of LDA as a base furnished the methylated α-nitro ketones 2a-c.Denitration of 2a, b with Bu3SnH/AIBN in dry benzene afforded the α'-methylated ketones 3a, b, which were converted to (+/-)-phoracantholide (4a) and (+/-)-dihydrorecifeiolide (4b), respectively, by the Bayer-Villiger oxidation.Reduction of 2c with NaBH4 and dehydration of the obtained nitro alkanol 5 with Al2O3/DMAP furnished the corresponding nitro alkene 6.Nef conversion of 6 with sodium hypophosphite and Raney nickel afforded (+/-)-muscone (7) in good yields. - Keywords: (+/-)-Phoracantholide / (+/-)-Recifeiolide / (+/-)-Muscone / α-Nitro ketones
- Ballini, Roberto,Marcantoni, Enrico,Petrini, Marino
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p. 1381 - 1384
(2007/10/02)
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- Catalytic enantioselective macrolide synthesis II: Use of differential deprotection protocols
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Catalytic enantioselective synthesis of Phorcantholide I has been achieved. Key stereochemistry was introduced using a chiral arene chromium tricarbonyl based catalyst to mediate the addition of dimethyl zinc to a functionalised aldehyde. During the synth
- Jones,Chapman,Huber,Beaty
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p. 1199 - 1202
(2007/10/02)
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- A New Synthesis of Medium Ring and Macrocyclic Acetylenic Lactones from Oxabicycloalkenones via their Tosylhydrazones
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Tosylhydrazones 4a-d of vinylogous lactones 1a-d on treatment with N-bromosuccinimide, under strictly controlled conditions, give the title acetylenic compounds 5a-d in 65-90percent yield.
- Mahajan, Jaswant Rai,Resck, Ines Sabioni
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p. 1748 - 1749
(2007/10/02)
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- Synthesis of (R)-(-)-phoracantholide I based on stereocontrolled cleavage of internal acetal
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Oxidation of (S)-2-butenyl-2-ethoxycarbonylcyclohexanone (6) with MCPBA afforded directly two chiral internal acetals, 1S,6S,9R-(8) and 1R,6S,9S-(9), instead of the epoxide. By treatment with BF3 etherate, the tertiary alcohol (12) obtained from 9 yielded an unexpected product (14) via the retro-aldol reaction and reconstruction of the internal acetal, and the expected fragmentation product (3) was not obtained. The mesylate of secondary alcohol (15b) prepared from 9 underwent silica-gel catalyzed, facile ring cleavage in a stereocontrolled fashion to afford the ring-enlarged 9-nonanolide derivatives (18). This methodology was applied for the synthesis of (R)-(-)-phoracantholide I. Examination using the Dreiding stereomodel provides a rationalized explanation for the stereocontrolled cleavage.
- Nagumo,Suemune,Sakai
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p. 8667 - 8676
(2007/10/02)
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- Carbocyclic ring expansion reactions via free radical pathways - Part III
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The free radical ring expansion methodology recently described1, leading to the formation of medium sized ring ketones from cyclohexanone precursors has been applied to different side chains and ring sizes. In addition precursors based on lactone rings have been prepared and subjected to radical forming reaction conditions.
- Baldwin, Jack E.,Adlington, Robert M.,Singh, Rajinder
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p. 3385 - 3412
(2007/10/02)
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- Synthesis of phoracantholide I based on stereospecific fragmentation reactions
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Phoracantholide I was synthesized on the basis of silica gel-catalyzed fragmentation to the ring-enlarged lactones.
- Nagumo,Suemune,Sakai
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p. 5585 - 5588
(2007/10/02)
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- Cyclization of 9-Substituted Decanoic Acid Derivatives to 9-Decanolide and 9-Decanelactam
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Several standard and some novel cyclization reactions have been applied to 9-substituted decanoic acids to establish which are the optimum procedures for lactonization and lactamization at 80 deg C under identical high-dilution conditions.The methods of Galli-Mandolini and Kellogg (cyclization of 9-bromodecanoate ion), Gerlach (cyclization of S-2-pyridyl 9-hydroxydecanethioate in the presence of AgClO4), and Yamaguchi (activation of the carboxyl group as a mixed anhydride) in the presence of an excess of DMAP appear to be the most useful for the preparation of the 10-membered lactone, phoracantolide I, under these conditions.Analogously, treatment of S-2-pyridyl 9-azidodecanethionate with Sn(SePh)3(1-) afforded the best yield of the 10-membered lactam.The mixed anhydrides RCOOCOAr (Ar = 2,4,6-trichlorophenyl) are more reactive than thioesters RCOSPy (Py = 2-pyridyl) with benzyl alcohol or benzylamine; it is confirmed that the addition of DMAP activates the reaction of alcohols with mixed anhydrides much more than with pyridyl thioesters, while the addition of Ag(1+) strongly activates RCOSPy in relation to either RCOOCOAr or RCOOSO2Mes.
- Bartra, Marti,Vilarrasa, Jaume
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p. 5132 - 5138
(2007/10/02)
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- Synthesis of two stereoisomers of the propanoate ester of 8-methyl-2-decanol using remote asymmetric induction
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A stereoselective synthesis of two isomers (2S,8R) and (2S,8S) of 8-methyl-2-decanol opanoate (the pheromone emitted by females of several Diabrotica species) has been accomplished using mote stereochemical relationships between carbons 3 and 9 of the 3,9-dimethyl decanolides 14 and 16.
- Ferrelra, J. Tercio B.,Simonelli, Fabio
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p. 6311 - 6318
(2007/10/02)
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- Iterative Synthesis of Selectively Substituted α,β-Unsaturated and Saturated Medium-Ring Lactones
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Chloro, chloromethyl and chlorofluoro carbenoids, generated by reaction of a base on the corresponding halides, were added to trimethylsilyl enol ethers derived from lactones, to give 1--2-chlorobicyclooxanes.Thermal rearrangement of these adducts led to the α,β-ethylenic lactones, corresponding to a one-carbon ring expansion of the starting lactones.After hydrogenation, with the same iterative sequence a new one-carbon ring expansion could be performed.This method allowed the preparation in good yields of hitherto unknown medium-ring lactones.Spectroscopic and physicochemical properties of the isomeric unsaturated lactones were examined.For the 9- and 10-membered series, the trans isomers could be readily isomerized by I2 into the cis isomers or gave diolides under acidic conditions.
- Fouque, Elie,Rousseau, Gerard,Seyden-Penne, Jacqueline
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p. 4807 - 4817
(2007/10/02)
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- Enzymatic Resolution of Medium-Ring Lactones. Synthesis of (S)-(+)-Phoracantholide I
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The horse liver and pig liver esterase hydrolysis of racemic medium ring lactones gives with excellent enantiomeric excess the S- (or R) lactones and the corresponding R- (or S) hydroxy acids.This is the first general method to obtain optically pure medium ring lactones.Application to the preparation of (S)-(+)-Phoracantholide I is reported.
- Fouque, Elie,Rousseau, Gerard
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p. 661 - 666
(2007/10/02)
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- Synthesis of Both the Enantiomers of Phoracantholide I; A Defensive Secretion of the Eucarypt Longicorn (Phoracantha synonyma), Employing Microbial Asymmetric Reduction with Immobilized Baker's Yeast
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Highly optically pure (R)- and (S)-phoracantholide I were synthesized in relatively short steps starting from diethyl 3-oxoglutarate by means of a microbial asymmetric reduction of the intermediate keto acid with immobilized baker's yeast entrapped in gels of κ-carrageenan.
- Naoshima, Yoshinobu,Hasegawa, Hidenobu,Nishiyama, Tadashi,Nakamura, Akihiro
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p. 608 - 610
(2007/10/02)
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- From Azido Acids to Macrolactams and Macrolactones
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A new method is reported for the conversion of azido acids into lactams, via thioester formation and in situ azide reduction and cyclisation under high-dilution conditions; since the quantitative conversion of macrolactams to macrolactones has been shown to be feasible, this results in an indirect, alternative macrolactonisation procedure.
- Bartra, Marti,Bou, Valenti,Garcia, Jordi,Urpi, Felix,Vilarrasa, Jaume
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p. 270 - 272
(2007/10/02)
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- Synthese de lactones a cycle moyen: Application a la synthese du pentadecanolide-15 et du phoracantholide I
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Medium ring size lactones can be prepared from bifunctional commercial starting compounds in high yields, using a few step sequence.Lactonisation is obtained by cyclization of the free ω-hydroxyacids or by the cyclization of ω-hydroxyacids having the hydroxy and carboxy group protected.
- Cossy, Janine,Pete, Jean-Pierre
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p. 989 - 994
(2007/10/02)
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- Synthesis of Both Enantiomers of Phoracantholide I, a Defensive Secretion of the Eucarypt Longicorn, Employing Asymmetric Reduction with Immobilized Baker's Yeast
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Highly enantiomerically pure (R)- and (S)-phoracantholide I were synthesized in relatively short steps starting from diethyl 3-oxoglutarate by means of an asymmetric reduction of the intermediate keto acid with immobilized baker's yeast.The asymmetric reduction with the immobilized baker's yeast gave greater facilities compared with the analogous reaction with free baker's yeast.
- Naoshima, Yoshinobu,Hasegawa, Hidenobu
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p. 2379 - 2382
(2007/10/02)
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- One-pot, four-different-component annulations: flexible and efficient conversion of n-sized cycloalkenones into n+4 alkenolides
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Five-, six-, and seven-membered conjugated cycloalkenones undergo one-pot conjugate addition with tri-n-butyltinlithium followed by 1,4-addition to vinyl ketones and then aldol addition to aldehydes leading to cyclic hemiketals 2. Lead tetraacetate oxidative fragmentation produces various 4-atom enlarged, vicinally disubstituted, regiospecifically and stereospecifically unsaturated macrolides 3.
- Posner, Gary H.,Asirvatham, Edward,Webb, Kevin S.,Jew, Sang-sup
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p. 5071 - 5074
(2007/10/02)
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- NEW GENERAL SYNTHESIS OF MEDIUM RING-LACTONES VIA A REGIOSELECTIVE β-SCISSION OF ALKOXYL RADICALS GENERATED FROM CATACONDENSED LACTOLS
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We describe a new general method for the synthesis of medium-sized lactones based on ring-enlargement via a regioselective β-scission of alkoxyl radicals generated by photolysis from the hypoiodites of several catacondensed lactols.The syntheses of 9-membered lactones from 6/5 fused lactols, 10-menbered lactones including a naturally occuring lactone, phoracantholide I, from 6/6 or 7/5 fused lactols, and 11-membered lactones from 7/6 or 8/5 fused lactols are shown to be achieved by the present method.This new method may have a potential for application to the synthesis of either smaller or larger-sized lactones.
- Suginome, Hiroshi,Yamada, Shinji
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p. 3371 - 3386
(2007/10/02)
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- Synthesis and Biological Activity of (+/-)-Pyrenolide B
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The synthesis and biological activity of (+/-)-pyrenolide B (1) and related compounds are described.The known (Z)-2-decen-9-olide (7) prepared via decan-9-olide (6) from 2-ethoxycarbonylcyclononanone (4) was converted to 9 by the deconjugative process, which, upon oxidation with m-chloroperbenzoic acid, led to the epoxy lactone 10.Base-promoted epoxide ring of 10 and subsequent oxidation furnished keto lactone 8, which, on treatment with phenylselenenyl chloride and subsequent oxidative elimination, provided (+/-)-pyrenolide B (1).The antimicrobial activity od (+/-)-1, 6, 7, 8, 9, 10a, 10b and 11a was examined against fungi and yeast.
- Suzuki, Soji,Tanaka, Akira,Yamashita, Kyohei
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p. 3095 - 3098
(2007/10/02)
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- A SYNTHESIS OF NOVEL NINE-MEMBERED DIENONES THROUGH A CYCLIC ACETYLENIC OXY-COPE REARRANGEMENT: THE SYNTHESIS OF dl-PHORACANTHOLIDE I
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Phoracantholide I, having a ten-membered lactone, was synthesized through a new synthetic method which includes a cyclic acetylenic oxy-Cope rearrangement and ring-expansion by the Baeyer-Villiger oxidation of a nine-membered ketone.
- Ohnuma, Takeshi,Hata, Noriaki,Miyachi, Nobuhide,Wakamatsu, Takeshi,Ban, Yoshio
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p. 219 - 222
(2007/10/02)
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- A THREE STEP SYNTHESIS OF EXALTOLIDE AND PHORACANTHOLIDE I
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The synthesis of phoracantholide I and exaltolide are described in 3 steps and in good yields.
- Cossy, J.,Pete, J.P.
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p. 2369 - 2370
(2007/10/02)
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- NEW GENERAL SYNTHESIS OF MEDIUM-SIZED LACTONES: A NEW ENTRY TO THE SYNTHESIS OF (+/-)-PHORACANTHOLIDE I
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We describe a new general method for the synthesis of medium-sized lactones under mild conditions involving β-scission of alkoxy radicals derived from catacondensed lactols as a key step and its application to an efficient new synthesis of a naturally occurring 10-membered lactone, phoracantholide I .
- Suginome, Hiroshi,Yamada, Shinji
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p. 3715 - 3718
(2007/10/02)
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- The Synthesis and the Absolute Configuration of Phoracantholide I and J; The Defensive Secretion of the Eucarypt Longicorn, Phoracantha synonyma
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Both enantiomers of phoracantholide I and J were synthesized from a chiral starting material obtainable via yeast reduction, and the absolute configurations of the natural materials were determined by GLC studies using a chiral stationary phase.
- Kitahara, Takeshi,Koseki, Koshi,Mori, Kenji
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p. 389 - 394
(2007/10/02)
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- Reactions of Haloketenes with Allyl Ethers and Thioethers: A New Type of Claisen Rearrangement
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A new reaction of dichloroketene (2) with allylic ethers, sulfides, and selenide 1 has been observed.A sigmatropic rearrangement takes place at room temperature, leading to α,α'-dichloro-γ,δ-unsaturated esters 3.The scope of this reaction was further investigated with dibromoketene (16), difluoroketene (17), electron-deficient chloroketenes, and different allylic systems.In the course of these studies, total syntheses of two naturally occurring macrolides, phoracantholide I and phoracantholide J, were achieved.Medium-ring conformations are discussed.
- Malherbe, Roger,Rist, Guenther,Bellus, Daniel
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p. 860 - 869
(2007/10/02)
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- (+/-)-Phoracantholid I via the Caesium Carbonate-promoted Ring Closure of the Methanesulphonate of 9-Hydroxydecanoic Acid
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(+/-)-Phoracantholid I, a product from the secretion of the longicorn Phoracantha synonyma, has been synthesised via the caesium carbonate treatment of the methanesulphonate of 9-hydroxydecanoic acid, prepared from the easily accessible 9-oxo-derivative.
- Barbier, Michel
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p. 668 - 669
(2007/10/02)
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- A NEW FUNGAL MORPHOGENIC SUBSTANCE, PYRENOLIDE A FROM PYRENOPHORA TERES
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A new ten-menbered lactone, pyrenolide A, was identified as a new fungal morphogenic substance and its structure including absolute stereochemistry was elucidated.
- Nukina, Manabu,Sassa, Takeshi,Ikeda, Michimasa
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p. 301 - 302
(2007/10/02)
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