- Synthesis of prostaglandin and phytoprostane B1 via regioselective intermodular pauson-khand reactions
-
A new approach to the synthesis of prostaglandin and phytoprostanes B 1 is described. The key step is an intermolecular Pauson-Khand reaction between a silyl-protected propargyl acetylene and ethylene. This reaction, promoted by NMO in the presence of 4 A molecular sieves, afforded the 3-fert-butyldimethylsilyloxymethyl-2-substituted-cyclopent-2-en-1- ones (III) in good yield and with complete regioselectivity. Deprotection of the silyl ether, followed by Swern oxidation, gave 3-formyl-2-substituted- cyclopent-2-en-1-ones (II). Julia olefination of the aldehydes II with the suitable chiral sulfone enabled preparation of PPB1 type I and PGB1.
- Vazquez-Romero, Ana,Cardenas, Lydia,Blasi, Emma,Verdaguer, Xavier,Riera, Antoni
-
-
Read Online
- Concise, scalable and enantioselective total synthesis of prostaglandins
-
Prostaglandins are among the most important natural isolates owing to their broad range of bioactivities and unique structures. However, current methods for the synthesis of prostaglandins suffer from low yields and lengthy steps. Here, we report a practicability-oriented synthetic strategy for the enantioselective and divergent synthesis of prostaglandins. In this approach, the multiply substituted five-membered rings in prostaglandins were constructed via the key enyne cycloisomerization with excellent selectivity (>20:1 d.r., 98% e.e.). The crucial chiral centre on the scaffold of the prostaglandins was installed using the asymmetric hydrogenation method (up to 98% yield and 98% e.e.). From our versatile common intermediates, a series of prostaglandins and related drugs could be produced in two steps, and fluprostenol could be prepared on a 20-gram scale. [Figure not available: see fulltext.]
- Zhang, Fuhao,Zeng, Jingwen,Gao, Mohan,Wang, Linzhou,Chen, Gen-Qiang,Lu, Yixin,Zhang, Xumu
-
p. 692 - 697
(2021/06/01)
-
- Synthesis of the C(7)-C(22) Sector of (+)-Acutiphycin via O-directed double free radical alkyne hydrostannation with Ph3SnH/Et3B, double I-Sn exchange, and double stille coupling
-
Herein a new double O-directed free radical hydrostannation reaction is reported on the structurally complex dialkyldiyne 11. Through our use of a conformation-restraining acetal to help prevent stereocenter-compromising 1,5-H-atom abstraction reactions b
- Hale, Karl J.,Maczka, Maciej,Kaur, Amarjit,Manaviazar, Soraya,Ostovar, Mehrnoosh,Grabski, Milosz
-
p. 1168 - 1171
(2014/03/21)
-
- Asymmetric hydroformylation of Z -Enamides and enol esters with rhodium-bisdiazaphos catalysts
-
Asymmetric hydroformylation (AHF) of Z-enamides and Z-enol esters provides chiral, alpha-functionalized aldehydes with high selectivity and atom economy. Rh-bisdiazaphospholane catalysts enable hydroformylation of these challenging disubstituted substrates under mild reaction conditions and low catalyst loadings. The synthesis of a protected analog of l-DOPA demonstrates the utility of AHF for enantioselective, atom-efficient synthesis of peptide precursors.
- Abrams, M. Leigh,Foarta, Floriana,Landis, Clark R.
-
p. 14583 - 14588
(2015/01/08)
-
- From enantiopure hydroxyaldehydes to complex heterocyclic scaffolds: Development of domino Petasis/diels-alder and cross-metathesis/Michael addition reactions
-
One-step assembly of hexahydroisoindole scaffolds by a sequence that combines the Petasis (borono-Mannich) and Diels-Alder reactions is described. The unique selectivity observed experimentally was confirmed by quantum calculations. The current method is
- Cannillo, Alexandre,Norsikian, Stéphanie,Tran Huu Dau, Marie-Elise,Retailleau, Pascal,Iorga, Bogdan I.,Beau, Jean-Marie
-
p. 12133 - 12143
(2015/03/31)
-
- Fast synthesis of complex enantiopure heterocyclic scaffolds by a tandem sequence of simple transformations on α-hydroxyaldehydes
-
Two tandems are faster than one! Properly sequenced reactions initiated by the Petasis aminoalcohol synthesis from boronic acids, diallylamine, and α-hydroxyaldehydes, including free aldoses, leads to rapid construction of complex enantiopure structures (see scheme). Copyright
- Cannillo, Alexandre,Norsikian, Stephanie,Retailleau, Pascal,Dau, Marie-Elise Tran Huu,Iorga, Bogdan I.,Beau, Jean-Marie
-
supporting information
p. 9127 - 9131
(2013/07/26)
-
- Synthesis of substituted α,β-unsaturated δ-lactones from vinyl tellurides
-
A new approach for the synthesis of α,β-unsaturated δ-lactones, a unit present in many natural products with interesting biological activities is described. The approach was based on the use of a vinyl telluride, and it is complementary to the methods usi
- Oliveira, Juliana M.,R. Freitas, Juliano C.,Comasseto, Jo?o Valdir,Menezes, Paulo Henrique
-
experimental part
p. 3003 - 3009
(2011/04/27)
-
- Syntheses of the macrolide subunits of merremoside-type resin glycosides
-
The 20- and 21-membered macrolide subunits of merremoside-type resin glycosides with interesting bioactivity were synthesized via a macrolactonization approach using Corey-Nicolaou protocol in 14 steps with overall yields of 0.7% for 17 and 3.5% for 18 fr
- Zhu, Xing-Mei,He, Li-Li,Yang, Guang-Li,Lei, Ming,Chen, Si-Shi,Yang, Jin-Song
-
p. 3510 - 3512
(2007/10/03)
-
- A route to 1,2-diols by enantioselective organocatalytic α-oxidation with molecular oxygen
-
A route to 1,2-diols by the direct organocatalytic enantioselective α-oxidation of aldehydes using molecular oxygen is presented. Protected commercially available chiral pyrrolidines catalyze the asymmetric α-oxidation of aldehydes with singlet molecular oxygen with high enantioselectivity to furnish the corresponding diols after in situ reduction in high yield with up to 98% ee. Electrophilic singlet molecular oxygen was photo or chemically generated ('dark' 1O2).
- Ibrahem, Ismail,Zhao, Gui-Ling,Sundén, Henrik,Córdova, Armando
-
p. 4659 - 4663
(2007/10/03)
-
- Catalytic enantioselective hydrogenation of vinyl bis(boronates)
-
Catalytic enantioselective hydrogenation of prochiral vinylmetallic reagents can provide an attractive alternative to hydrometalation and bismetalation of alkenes. In this contribution, the first highly enantioselective hydrogenation of vinyl boronic esters is described. The chiral reduction products are versatile intermediates for chemical synthesis. Copyright
- Morgan, Jeremy B.,Morken, James P.
-
p. 15338 - 15339
(2007/10/03)
-
- A practical enantioselective synthesis of massoialactone via hydrolytic kinetic resolution
-
An efficient enantioselective synthesis of (R)- and (S)-massoialactone has been achieved. The key steps are the hydrolytic kinetic resolution of a racemic epoxyheptane with (R,R)-(salen)-CoIIIOAc complex and ring-closing metathesis of homoallylic alcohol derived acrylate esters using Grubb's catalyst.
- Gupta, Priti,Naidu, S. Vasudeva,Kumar, Pradeep
-
p. 849 - 851
(2007/10/03)
-
- The kinetic resolution of allylic alcohols by a non-enzymatic acylation catalyst; application to natural product synthesis
-
A planar-chiral DMAP derivative is shown to serve as an effective catalyst for the kinetic resolution of allylic alcohols; to illustrate its practical utility, the catalyst is applied to the resolution of two alcohols that have been employed as intermedia
- Bellemin-Laponnaz, Stephane,Tweddell, Jennifer,Ruble, J. Craig,Breitling, Frank M.,Fu, Gregory C.
-
p. 1009 - 1010
(2007/10/03)
-
- Asymmetric synthesis of (S)-Massoialactone
-
An asymmetric synthesis of (S)-(+)-Massoialactone is described using the Sharpless asymmetric dihydroxylation and the regiospecific nucleophilic opening of a cyclic sulfate as key steps.
- Pais, Godwin C.G.,Fernandes, Rodney A.,Kumar, Pradeep
-
p. 13445 - 13450
(2007/10/03)
-
- The asymmetric ene reaction of N-glyoxyloyl-(2R)-bornane-10,2-sultam with 1-pentene and 1-hexene
-
The asymmetric ene reaction of N-glyoxyloyl-(2R)-bornane-10,2-sultam 2 and its hemiacetal 3 with 1-pentene 4 and 1-hexene 5 in the presence of Lewis acids is reported. All the ene reactions studied led to diastereoisomeric mixtures of olefins 6 and 7 or 8 and 9, with predominance of products of the (S) absolute configuration on the newly formed stereogenic center. The absolute configuration (via X-ray analysis of 6 and chemical correlation) and the extent of asymmetric induction were established. Stereochemical models are proposed.
- Jezewski, Artur,Chajewska, Katarzyna,Wielogorski, Zbigniew,Jurczak, Janusz
-
p. 1741 - 1749
(2007/10/03)
-
- Highly Stereoselective Synthesis of Trifluoromethylated Compounds via Ester-Enolate [2,3]-Wittig and [3,3]-Ireland-Claisen Rearrangements
-
γ-Trifluoromethylated propargylic alcohols have been obtained in optically pure forms via effective enzymatic kinetic resolution and then converted into (E)- or (Z)-allylic alcohols. [2,3]-Wittig rearrangement of the corresponding [[γ-(trifluoromethyl)allyl]oxy]acetic acid methyl esters afforded α-hydroxy-β-(trifluoromethyl)-γ,σ-unsaturated carboxylic acid methyl esters in good yields. The rearrangement of (Z)-substrates proceeded in a highly stereoselective manner to give anti-isomers with E configuration at a newly created olefinic bond via complete chirality transfer. (E)-Substrates, however, showed relatively low stereoselectivities resulting in mixtures of syn- and anti-products. The trifluoromethylated allylic alcohols were also converted into the corresponding α-methoxyacetic acid γ-(trifluoromethyl)allyl esters and evaluated as substrates for [3,3]-Ireland-Claisen rearrangement. (E)-Substrates were efficiently transformed into syn-products while (Z)-substrates exhibited relatively low stereoselectivities. The two complementary methods provide facile routes to highly functionalized trifluoromethyl-containing molecules with a high degree of stereocontrol.
- Konno, Tsutomu,Umetani, Hideki,Kitazume, Tomoya
-
p. 137 - 150
(2007/10/03)
-
- Total syntheses of (+)-acutiphycin and (+)-trans-20,21-didehydroacutiphycin
-
The first total syntheses of the cytotoxic macrolides (+)-acutiphycin (1) and (+)-trans-20,21-didehydroacutiphycin (2) have been achieved. An acyclic stereocontrol strategy was employed to establish the configurations at C(5), C(10), and C(13) as well as the E geometry of the C(8,9)-trisubstituted olefin. Importantly, the natural source of 1 and 2, the blue-green alga Osillatoria acutissima, no longer produces these metabolites.
- Smith III, Amos B.,Chen, Sean S.-Y.,Nelson, Frances C.,Reichert, Janice M.,Salvatore, Brian A.
-
p. 10935 - 10946
(2007/10/03)
-
- Lipase-Catalyzed Enantiomer Selective Hydrolysis of 1,2-Diol Diacetates
-
Enantiomer selective hydrolysis of racemic 1,2-diol diacetates (rac-2a-h) was investigated by using the inexpensive commercial porcine pancreatic lipase.The hydrolysis proceeds with variable regioselectivity but with moderate to good enantioselectivity yielding a mixture of isomeric monoacetates (3a-h and 4a-h) and unchanged diacetate enantiomers (2a-h).Evidence was found that both monoacetates (3a-h and 4a-h) are formed with the same sense of enantiomer selectivity.
- Poppe, Laszlo,Novak, Lajos,Kajtar-Peredy, Maria,Szantay, Csaba
-
p. 2211 - 2218
(2007/10/02)
-
- Asymmetric Dihydroxylation of Olefins with a Simple Chiral Ligand
-
A C2 symmetrical chiral ligand derived from (R,R)-trans-1,2-diaminocyclohexane is highly effective in the asymmetric cis-dihydroxylation of aromatic and aliphatic di- and trisubstituted olefins under stoichiometric conditions.
- Hanessian, Stephen,Meffre, Patrick,Girard, Mario,Beaudoin, Serge,Sanceau, Jean-Yves,Bennani, Youssef
-
p. 1991 - 1993
(2007/10/02)
-
- A Systematic Study on the Bakers'Yeast Reduction of 2-Oxoalkyl Benzoates and 1-Chloro-2-alkanones
-
The bakers' yeast reduction of a series of 2-oxoalkyl arenecarboxylates (1a-f) (R=CH3 to n-C6H13; X=H) and the phenyl-modified derivatives (1g-l) (R=n-C5H11, X=OH, CH3, F, Cl, Br, or I) as well as 1-chloro-2-alkanones R(C=O)CH2Cl (6a-f) (R=CH3 to n-C6H13) were systematically investigated.The substrate specificities, configuration and percentee of the reduction products were found to be highly dependent on the length of the alkyl group (R) and the α substituent.Thus, the benzoates 1a-f gave optically active 2-hydroxyalkyl benzoates (2a-f) (R, configuration, percentee) (a: CH3, S, 99; b: C2H5, S, 98; c: C3H7, S, 26; d: n-C4H9, R, 55; e: n-C5H11, S, 15; f: n-C6H13, S, 63) in 11-91percent yields.Among the modification experiments of the phenyl group, 1g-l, the p-iodo substituent markedly increased the ee from 15 to 71percent, although the yield was rather lowered (22percent yield).The reduction of α-chloro ketones 6a-f also gave optically active 1-chloro-2-alkanols (7a-f) in 16-69percent yields.
- Sakai, Takashi,Wada, Kou,Murakami, Takahiko,Kohra, Kiichiro,Imajo, Norihisa,et al.
-
p. 631 - 638
(2007/10/02)
-
- A CONVENIENT SYNTHESIS OF HOMOCHIRAL δ-ALKYLATED α,β-UNSATURATED δ-LACTONES
-
The tert-butyl propiolate ion serves as a convenient and efficient nucleophile in boron trifluoride-catalyzed openings of homochiral, mono-substituted epoxides.The resulting tert-butyl 5-hydroxy-2-alkynoates are converted into the title compounds upon semihydrogenation followed by acid hydrolysis.Specific examples include the synthesis of parasorbic acid and massoilactone, two naturally derived lactones of the present type.The scope of the synthetic protocol is discussed.
- Hoeyer, Thomas,Kjaer, Anders,Lykkesfeldt, Jens
-
p. 1042 - 1051
(2007/10/02)
-
- The Use of ?-Allyltricarbonyliron Lactone Complexes in the Synthesis of the β-Lactone Esterase Inhibitor (-)-Valilactone.
-
A concise synthesis of the β-lactone esterase inhibitor valilactone (2) is reported.This synthesis employs the stereoselective preparation of a ?-allyltricarbonyliron lactone complex (7) that on oxidation with ceric ammonium nitrate, affords an appropriat
- Bates, Roderick W.,Fernandez-Moro, Rosalina,Ley, Steven V.
-
p. 9929 - 9938
(2007/10/02)
-
- High-yield Production of Optically Active 1,2-Diols from the Corresponding Racemates by Microbial Stereoinversion
-
A novel method for producing optically active 1,2-diols by microbial stereoinversion was developed.It was found that some microorganisms could convert only (R)-1,2-pentanediol in the racemate to the (S)-enantiomer.Candida parapsilosis produced 27.9 g/l of (S)-1,2-pentanediol from 30 g/l of the racemate in 24 hr of reaction (molar yield 93percent, enantiomeric excess 100percent).This stereoinversion proceeded via oxidation of (R)-1,2-pentanediol to 1-hydroxy-2-pentanone by an NAD+-linked (R)-specific alcohol dehydrogenase and reduction of 1-hydroxy-2-pentanone to (S)-1,2-pentanediol by an NADPH-linked (S)-specific 2-keto-1-alcohol reductase.This microbial stereoinversion was applicable to ten 1,2-diols.Optically active 1,2-diols prepared by the reaction had the same configuration at the chiral center.
- Hasegawa, Junzo,Ogura, Masahiro,Tsuda, Satoru,Maemoto, Shun-ichi,Kutsuki, Hidetoshi,Ohashi, Takehisa
-
p. 1819 - 1827
(2007/10/02)
-
- Asymmetric Dihyroxylation of Alkenes with Osmium Tetroxide: Chiral N,N'-Dialkyl-2,2'-bipyrrolidine Complex
-
Asymmetric osmylation of alkenes by using N,N'-dialkyl-2,2'-bipyrrolidines as the chiral ligands shows a high asymmetric induction and a marked dependence of the enantioselectivity on both the N-alkyl group and the reaction solvent.
- Hirama, Masahiro,Oishi, Tohru,Ito, Sho
-
p. 665 - 666
(2007/10/02)
-
- Stereochemical Control on Yeast Reduction of α-Keto Esters. Reduction by Immobilized Bakers' Yeast in Hexane
-
Ethyl 2-oxoheptanoate has been reduced by three methods: free bakers' yeast (FBY) in water, immobilized bakers' yeast (IMBY) in water, and IMBY in hexane.It has been found that the stereochemistry of reduction of α-keto esters by bakers' yeast is controlled by appropiate choice of reaction conditions.
- Nakamura, Kaoru,Inoue, Kiyoko,Ushio, Kazutoshi,Oka, Shinzaburo,Ohno, Atsuyoshi
-
p. 2589 - 2593
(2007/10/02)
-
- ASYMMETRIC OXIDATION OF OLEFINS TO VICINAL DIOLS WITH OSMIUM TETROXIDE
-
High levels of asymmetry can be achieved in the osmium tetroxide cis-hydroxylation of olefins by employing (-)-(R,R)-N,N,N',N'-tetramethylcyclohexane-1,2-trans-diamine as a chiral ligand for the osmium.
- Tokles, Maritherese,Snyder, John K.
-
p. 3951 - 3954
(2007/10/02)
-
- Facile Synthesis of 1,2:5,6-Di-O-cyclohexylidene-D-mannitol and 2,3-O-Cyclohexylidene-D-glyceraldehyde
-
The reaction of cyclohexanone diethyl acetal with D-mannitol yielded quantitatively 1,2:5,6-di-O-cyclohexylidene-D-mannitol (1) and its isomer (2).From 1, 2,3-O-cyclohexylidene-D-glyceraldehyde (3) was obtained in a quantitative yield without racemization.
- Sugiyama, Takeyoshi,Sugawara, Hidehiko,Watanabe, Masashi,Yamashita, Kyohei
-
p. 1841 - 1844
(2007/10/02)
-
- AN ASYMMETRIC SYNTHESIS OF α-BENZYLOXY ALDEHYDES HAVING A CHIRAL TERTIARY CENTER - AN APPLICATION TO THE ASYMMETRIC SYNTHESIS OF exo-(+)-BREVICOMIN -
-
α-benzyloxy aldehydes having a chiral tertiary center at α-carbon atom are synthesized in high enantiomeric excess by successive treatment of 2-methoxycarbonyl-3-phenyl-1,3-diazabicyclooctane with diisobutylaluminum hydride (DIBAL-H) and Grignard reagents.The asymmetric reaction is applied to the total synthesis of exo-(+)-brevicomin.
- Asami, Masatoshi,Mukaiyama, Teruaki
-
-
- SYNTHESIS OF THE TWO ENANTIOMERIC FORMS OF 5-HEXADECANOLIDE PROPOSED PHEROMONE COMPONENT FROM VESPA ORIENTALIS
-
The first synthesis of R-(+)-5-hexadecanolide 1 and of it's S isomer 2 has been achieved in 9 steps, from the C4 chiral synthon 3; the absolute configuration is determined by conversion of the key intermediates 12 and 13 into R-and S-1,2-heptandiol.
- Servi, Stefano
-
p. 2023 - 2024
(2007/10/02)
-
- Prostaglandins. 2. Synthesis of Prostaglandin F2α in Optically Active Form from Chiral Precursors
-
A synthetic route to optically active prostaglandins is described which use chiral starting materials.Acylation of the bis(magnesiobromide) salt of methyl hemimalonate with (S)-(-)-2-acetoxysuccinyl chloride led to unstable dimethyl (S)-4-acetoxy-3,6-diox
- Johnson, Francis,Paul, K.G.,Favara, Duccio,Ciabatti, Romeo,Guzzi, Umberto
-
p. 2190 - 2198
(2007/10/02)
-