- Ultrasound-accelerated synthesis of chiral allylic alcohols promoted by indium metal
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The 2-iodomethyl-O-isopropylidine acetals undergo smoothly β-elimination by indium metal in methanol under sonication to afford the corresponding allylic alcohols in excellent yields with high selectivity. This method tolerates both acid and base labile functional and protecting groups and also free hydroxyl groups present in the molecule. Improved yields and enhanced rates are the remarkable features obtained by ultrasound.
- Yadav,Reddy,Srinivasa Reddy
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Read Online
- Synthesis of optically active allylic alcohols
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A practical and enantiospecific method for the synthesis of optically pure allylic alcohols [(R)- or (S)-1-alken-3-ols] is described. The key reaction is the reductive cleavage of the cyclic carbonates of 1-halo-2,3-alkanediols with zinc, magnesium, or samarium diiodide.
- Kang,Kim,Cho,Jeon
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Read Online
- An Iterative Phosphate Tether Mediated Approach for the Synthesis of Complex Polyol Subunits
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A pot-economical approach to advanced polyol subunits is reported. The key reactions involved are iterative use of a phosphate tether-mediated one-pot sequential RCM/CM/H2 with subsequent utilization of either a regio-/diasteroselective cuprate addition or a Pd-catalyzed reductive allylic transposition. This method highlights the asymmetric synthesis of 12 complex polyol subunits in 4–6 one-pot sequential operations with a total of 12–14 reactions, of which 4–5 are catalytic, with minimal workup and purification procedures.
- Javed, Salim,Ganguly, Arghya,Dissanayake, Gihan C.,Hanson, Paul R.
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supporting information
p. 16 - 21
(2021/12/27)
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- Total Synthesis of the Echinodermatous Ganglioside LLG-3 Possessing the Biological Function of Promoting the Neurite Outgrowth
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A total synthesis of echinodermatous ganglioside LLG-3 with neuritogenic activity was accomplished by a convergent strategy. The synthesis of 2-hydroxyethyl 8-O-Me-α-sialoside 2 was started from the phenyl 7,8-di-O-Pico-thiosialoside 5, which can be chemoselectively removed the picoloyl group, and then the methyl group in 8-O-MeNeu5Ac moiety was chemoselectively prepared using TMSCHN2/FeCl3. For preparation of the terminal disialic unit, oxidative amidation was initially utilized by our group to efficiently construct the α(2,11) linkage of 8-O-Me-Neu5Acα(2,11)Neu5Gc. Herein, we also demonstrate that the synthesized ganglioside LLG-3 exhibited the neuritogenic activity toward the primary cortical neurons and that biological activity is superior to that of ganglioside DSG-A.
- Huang, Yuahn-Sieh,Shih, Jing-Feng,Tsai, Yow-Fu,Wu, Yu-Fa
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supporting information
p. 7491 - 7495
(2020/10/09)
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- Regio- and stereoretentive synthesis of branched, linear (E)- and (Z)-allyl fluorides from allyl carbonates under Ir-catalysis
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This paper describes a new catalytic method for the regio- and stereocontrolled fluorination of allylic carbonates. This transformation uses TBAF·4tBuOH as the fluoride source and [Ir(COD)Cl]2 as the catalyst; the most commonly used [Ir(COD)Cl]2/phosphoramidite system is ineffective. Synthetically, this reaction is characterized by a high degree of structural conservation in going from substrates to the products. The fluorination of (E)-allylic carbonates leading to linear (E)-allylic fluorides (l : b > 20 : 1, E : Z > 20 : 1) is unprecedented and a unique feature of fluoride as the nucleophile. The first examples of transition metal catalyzed fluorination affording (Z)-allyl fluorides (Z : E ratio >20 : 1) are disclosed along with the successful fluorination of branched, linear (E)- and (Z)-allyl carbonates with [18F] fluoride in the presence of [Ir(COD)Cl]2. 18O-Labeling of the reactant reveals internal return during the allylic ionization step, and pathways for effective intra- and intermolecular isotope exchange.
- Benedetto, Elena,Tredwell, Matthew,Hollingworth, Charlotte,Khotavivattana, Tanatorn,Brown, John M.,Gouverneur, Veronique
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- Asymmetric synthesis of a 12-membered macrolactone core and a 6-epi analogue of amphidinolide W from 4-pentenoic acid
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A flexible and efficient asymmetric route to the synthesis of a 12-membered macrolactone core and a 6-epi analogue of amphidinolide W has been accomplished from commercially available 4-pentenoic acid. The successful generation of stereocenters was achieved by utilizing an Evans' chiral auxiliary-based alkylation and aldol reaction. Other key reactions such as a Julia-Kocienski olefination, Kita's macrolactonization, ring closing metathesis (RCM) reaction, and Yamaguchi's esterification were significant for the construction of the macrolactone cores.
- Chatterjee, Bhaskar,Mondal, Dhananjoy,Bera, Smritilekha
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p. 1170 - 1185,16
(2020/09/09)
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- Stereoselective synthesis of tetrahydropyrans through tandem and organocatalytic oxa-Michael reactions: Synthesis of the tetrahydropyran cores of ent-(+)-sorangicin A
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Tandem and organocatalytic oxa-Michael reactions of α,β- unsaturated aldehydes were explored for the stereoselective synthesis of structurally complex tetrahydropyrans. Thestereoselective synthesis of 2,6-trans-tetrahydropyrans, which are thermodynamically unfavorable, was accomplished through a reagent-controlled, organocatalytic oxa-Michael reaction. A temperature-dependent configurational switch allowed the preparation of both 2,3-trans-2,6-trans-and 2,3-cis-2,6-cis-tetrahydropyrans from a common substrate. This switch was then used to synthesize the precursors of the C21-C29 and C30-C37 fragments of ent-(+)-sorangicin A. The tandem and organocatalytic oxa-Michael reactions of α,β-unsaturated aldehydes were explored and applied to the stereoselective synthesis of structurally complex tetrahydropyrans. Copyright
- Lee, Kiyoun,Kim, Hyoungsu,Hong, Jiyong
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p. 1025 - 1032
(2012/03/27)
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- Enantioselective synthesis of possible diastereomers of heptadeca-1-ene-4,6-diyne-3,8,9,10-tetrol; Putative structure of a conjugated diyne natural product isolated from hydrocotyle leucocephala
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Enantioselective synthesis of possible diastereomers of heptadeca-1-ene-4,6-diyne-3,8,9,10-tetrol, a structure proposed for the natural product isolated from Hydrocotyle leucocephala is accomplished. The reported spectral data of the natural product did n
- Prasad, Kavirayani R.,Swain, Bandita
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experimental part
p. 2029 - 2039
(2011/05/19)
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- Formal synthesis of the bryostatin Northern Hemisphere: Asymmetric synthesis of the B ring and C1-C9 fragment
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A formal synthesis of the top half fragment of bryostatin 11 has been developed. Stereoselective construction of the B ring was achieved by using a ring-closing metathesis reaction in conjunction with asymmetric glycolate alkylation. Furthermore, the C1-C9 fragment was synthesized by Brown allylation, chelation-controlled aldol condensation, and Saksena-Evans reduction to construct all stereogenic centers. Georg Thieme Verlag Stuttgart - New York.
- Nakagawa-Goto, Kyoko,Crimmins, Michael T.
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scheme or table
p. 1413 - 1418
(2011/08/03)
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- Stereoselective synthesis of 2,6-trans-tetrahydropyran via primary diamine-catalyzed oxa-conjugate addition reaction of α,β-unsaturated ketone: Total synthesis of psymberin
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The total synthesis of psymberin was achieved employing a readily available chiral epoxide to prepare two of the three subunits in the natural product. The key reaction was a highly stereoselective organocatalytic oxa-conjugate addition reaction of α,β-un
- Byeon, Seong Rim,Park, Heekwang,Kim, Hyoungsu,Hong, Jiyong
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supporting information; experimental part
p. 5816 - 5819
(2012/01/06)
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- CYCLIC AMINE COMPOUND
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The present invention provides an excellent antihypertensive medicament. The medicament of the present invention comprises a compound having the general formula (I) and the like: [wherein R1: H, substitutable alkyl, substitutable alkenyl, substitutable cyclic hydrocarbon, substitutable heterocyclyl or the like; R2: H, substitutable alkyl, substitutable alkenyl, substitutable cycloalkyl or the like; R3, R4; H, substitutable alkyl, substitutable alkenyl, substitutable cycloalkyl or the like; R5, R6: H, substitutable alkyl, substitutable cycloalkyl, substitutable alkoxy or the like; R7, R8: H, substitutable alkyl, substitutable cycloalkyl or the like; X: the formula (II) or the like; A: substitutable cyclic hydrocarbon, substitutable heterocyclyl or the like; Y: a single bond, substitutable alkylene, substitutable alkenylene, -(CH2)a-X1-(CH2)b- (X1: the formula -NH-, -O- or the like; a, b: 0-5) or the like; B: substitutable cyclic hydrocarbon, substitutable heterocyclyl or the like].
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Page/Page column 147-148
(2009/04/23)
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- An RCM strategy to stereodiverse δ-sultam scaffolds
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(Chemicall Equation Presented) An asymmetric approach for the synthesis of substituted δ-sultams with multiple synthetic handles is described. This study demonstrates the facile construction of a stereochemically diverse array of substituted δ-sultams, more specifically substituted 3,4,5,6-dihydro 1,2-thiazine 1,1-dioxides. A pivotal Mitsunobu alkylation/RCM sequence is used to assemble key allyl sultam building blocks possessing a C3 stereogenic handle. All subsequent reactions are achieved with high levels of diastereoselectivity to afford enantiopure δ-sultams in good yields.
- Jimenez-Hopkins, Maria,Hanson, Paul R.
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scheme or table
p. 2223 - 2226
(2009/05/11)
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- An intramolecular Diels-Alder approach to the eunicellins: Enantioselective total syntheses of ophirin B and astrogorgin
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The enantioselective syntheses of the eunicellins ophirin B and astrogorgin have been completed. Ring-closing metatheses provide efficient access to the oxonene rings, and highly diastereoselective intramolecular Diels-Alder reactions resulted in the form
- Crimmins, Michael T.,Brown, Brandon H.,Plake, Hilary R.
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p. 1371 - 1378
(2007/10/03)
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- Divalent activation in temporary phosphate tethers: Highly selective cuprate displacement reactions
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(Chemical Equation Presented) Desymmetrization of a readily derived psuedo-C2-symmetric monocyclic phosphate via highly diastereoselective anti-SN2′ allylic displacement reactions is reported. This method utilizes of a wide variety o
- Whitehead, Alan,McParland, James P.,Hanson, Paul R.
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p. 5025 - 5028
(2007/10/03)
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- P-heterocyclic building blocks: Application to the stereoselective synthesis of P-sugars
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A strategy relying on the utilization of stereoselective additions to allyldiphenylphosphonate esters and subsequent ring-closing metathesis (RCM) to access P-chiral P-heterocyclic building blocks for the synthesis of phosphono sugars is described. These
- Stoianova, Diana S.,Whitehead, Alan,Hanson, Paul R.
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p. 5880 - 5889
(2007/10/03)
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- Stereoselective photochemical 1,3-dioxolane addition to 5-alkoxymethyl-2(5H)-furanone: Synthesis of bis-tetrahydrofuranyl ligand for HIV protease inhibitor UIC-94017 (TMC-114)
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A convenient synthesis of (3R,3aS,6aR)-3-hydroxyhexahydrofuro[2,3-b]furan, a high-affinity non-peptidal ligand for HIV protease inhibitor UIC-94017, is described. This inhibitor is undergoing advanced clinical trials. The synthesis utilizes a novel stereoselective photochemical 1,3-dioxolane addition to 5(S)-benzyloxymethyl-2(5H)-furanone as the key step. The requisite furanone derivative was prepared in high enantiomeric excess by an immobilized lipase-catalyzed selective acylation of (±)-1-(benzyloxy)-3-buten-2-ol and a ring-closing olefin metathesis with Grubbs' catalyst. Optically active bis-THF was converted to protease inhibitor 2 (UIC-94017).
- Ghosh, Arun K.,Leshchenko, Sofiya,Noetzel, Marcus
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p. 7822 - 7829
(2007/10/03)
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- METHOD OF PREPARING (3R, 3aS, 6aR) -3- HYDROXYHEXAHYDROFURO [2, 3-b] FURAN AND RELATED COMPOUNDS
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A method of synthesizing (3R, 3aS, 6aR) -3- hydroxyhexahydrofuro [2, 3-b] furan (I), and related compounds, in high yield and high enantiomeric selectivity is disclosed. Also disclosed is a method of manufacturing (5S) -5-(benzyloxymethyl) -5H-furan-2-one.
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- Enantioselective total synthesis of (+)-gigantecin: Exploiting the asymmetric glycolate aldol reaction
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The enantioselective synthesis of the potent, selective, cytotoxic, annonaceous acetogenin, (+)-gigantecin, has been completed. An asymmetric glycolate aldol serves to establish the stereocenters at C13,14 and at C21,22. A Carreira asymmetric acetylide ad
- Crimmins, Michael T.,She, Jin
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p. 12790 - 12791
(2007/10/03)
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- A unified approach to the enantioselective synthesis of 2,6-cis and trans disubstituted tetrahydropyranones
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A stereoselective construction of cis- and trans-2,6-disubstituted tetrahydropyranones, based on strategy which combines an asymmetric alkylation and ring closing metathesis for the formation of a cyclic enol ether, is reported.
- Crimmins, Michael T.,Diaz, Caroline J.,Emmitte, Kyle A.
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p. 179 - 183
(2007/10/03)
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- Ah intramolecular Diels-Alder approach to the eunicelins: Enantioselective total synthesis of ophirin B
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The enantioselective synthesis of the eunicellin ophirin B has been completed. A ring-closing metathesis provides efficient access to the oxonene ring, and a highly diastereoselective intramolecular Diels-Alder reaction results in the formation of the hyd
- Crimmins, Michael T.,Brown, Brandon H.
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p. 10264 - 10266
(2007/10/03)
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- Synthesis of amino-1,4-anhydro-D-pentitols and amino-1,5-anhydro-D-hexitols with the arabino configuration from (R)-glycidol
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2-Amino-1,4-anhydro-pentitol and 3-amino-1,5-anhydro-4-deoxy-hexitol with the arabino configuration were synthesised from (R)-glycidol using a metathesis reaction as the key step. The dihydrofuran or dihydropyran products obtained after the metathesis rea
- Aragones, Silvia,Bravo, Fernando,Diaz, Yolanda,Matheu, Ma. Isabel,Castillon, Sergio
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p. 1847 - 1856
(2007/10/03)
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- New synthesis of sn-1,2- and sn-2,3-O-diacylglycerols application to the synthesis of enantiopure phosphonates analogous to triglycerides: A new class of inhibitors of lipases
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Phosphonate compounds mimic the first transition state occurring during enzymatic carboxyester hydrolysis of natural substrates by forming a covalent bond with the catalytic serine. However, until now the organophosphorus compounds used in the inhibition studies more or less resembled a natural triglyceride substrate. In order to elucidate the interfacial activation and the mechanism of action of lipases, specific inhibitors need to be prepared. To achieve this goal, enantiomerically pure sn-1,2- and sn-2,3O- didecanoylglycerol compounds were prepared - starting from a C-4 chiral synthon, 3-buten-1,2-diol - and treated with n-pentylphosphonic dichloride and p-nitrophenol to afford the corresponding diastereomeric phosphonates, which were acylglycerol analogs. Subsequent separation of each of the phosphonate diastereomers A/B or ent-A/ent-B, performed by HPLC, led to four enantiopure stereoisomers that will be investigated as inhibitors of Human Pancreatic Lipase (HPL) and Human Gastric Lipase (HGL) using the monomolecular film technique.
- Marguet, Frank,Cavalier, Jean-Francois,Verger, Robert,Buono, Gerard
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p. 1671 - 1678
(2007/10/03)
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- Asymmetric syntheses of chiral allylic alcohols
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Chiral allylic alcohols 2 can easily be obtained by elimination from iodo ketals 10. These are available from natural sources, or by application of the asymmetric Sharpless dihydroxylation to vinylogous esters 6, subsequent reduction, halogenation and elimination. This protocol allows the synthesis of highly functionalized allylic alcohols, which can be used in asymmetric Claisen rearrangements.
- Schneider, Christiane,Kazmaier, Uli
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p. 1314 - 1320
(2007/10/03)
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- One-pot transformation of p-toluenesulfonates of 2,3-epoxy alcohols into allylic alcohols
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A convenient and efficient method for the synthesis of synthetically useful non-racemic allylic alcohols from 4-methylbenzenesulfonates of non- racemic 2,3-epoxy alcohols is described. Satisfactory yields are obtained by treatment of 4-methylbenzenesulfonates of non-racemic 2,3-epoxy alcohols with potassium iodide followed by zinc powder and ammonium chloride in a one-pot manner. The method has been successfully applied to the synthesis of a key building block of C30-C37 botryococcenes.
- Habashita, Hiromu,Kawasaki, Takeshi,Akaji, Masako,Tamamura, Hirokazu,Kimachi, Tetsutaro,Fujii, Nobutaka,Ibuka, Toshiro
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p. 8307 - 8310
(2007/10/03)
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- Simple one-pot transformations of toluene-p-sulfonates of 2,3-epoxy alcohols into allylic alcohols
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A simple synthetic method for the preparation of scalemic allylic alcohols from toluene-p-sulfonates of scalemic 2,3-epoxy alcohols is reported. Satisfactory yields are obtained by treatment of toluene-p-sulfonates of 2,3-epoxy alcohols with potassium iodide followed by triphenylphosphine and iodine in a one-pot synthesis.
- Fujii, Nobutaka,Habashita, Hiromu,Akaji, Masako,Nakai, Kazuo,Ibuka, Toshiro,Fujiwara, Masahiro,Tamamura, Hirokazu,Yamamoto, Yoshinori
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p. 865 - 866
(2007/10/03)
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- A Stereocontrolled Route to Both Enantiomers of the Necine Base Dihydroxyheliotridane via Intramolecular 1,3-Dipolar Addition Using the Same Chiral Precursor
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Diastereofacial selectivity in an enantiospecific intramolecular 1,3-dipolar addition is controlled by adjusting the size of the tether between the dipole and the dipolarophile to give 2,3-disubstituted pyrrolidines enantiomeric with respect to the newly
- Hashimura, Kazuya,Tomita, Shun'ichi,Hiroya, Kou,Ogasawara, Kunio
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p. 2291 - 2292
(2007/10/02)
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- Larger Scale Preparation of Optically-active Allylic Alcohols
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An efficient and practical synthesis of optically-active allylic alcohols from 2,3-epoxytoluene-p-sulfonates by the in situ formation of the epoxy iodides and their subsequent reduction with zinc-copper couple has been established.Application of this procedure to the larger-scale synthesis of (S)-(+)-but-3-en-2-ol from (2S,3S)-3-methylglycidyl toluene-p-sulfonate has also been investigated.
- Balmer, Ethnie,Germain, Andrew,Jackson, William P.,Lygo, Barry
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p. 399 - 400
(2007/10/02)
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- Reductive Cleavage Reaction of γ-Functionalized α,β-Unsaturated Esters and Halomethyls Mediated with Magnesium in Methanol
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Reductive cleavage of various types of C-O and C-N bonds tethered to α,β-unsaturated esters and halomethyls was mediated with magnesium in methanol, which provided a facile method for the synthesis of δ-hydroxy or δ-amino β,γ-unsaturated esters and allylic alcohols.Regardless of the geometry (E or Z) of the α,β-unsaturated esters, 1a-b, 5a-c, 11, 13, and 23, the cleavage product obtained was exclusively the E isomer of the corresponding deconjugated hydroxy and amino esters.The steric bias and ring strain of 15, 17, and 21 gave rise to a product mixture of E and Z isomers.
- Pak, Chwang Siek,Lee, Eun,Lee, Ge Hyeong
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p. 1523 - 1530
(2007/10/02)
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- A Tellurium Transposition Route to Allylic Alcohols: Overcoming Some Limitations of the Sharpless-Katsuki Asymmetric Epoxidation
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Good yields of enantiomeric allylic alcohols can be obtained in high enantiomeric excess (ee) by combining Sharpless-Katsuki asymmetric epoxidation process (SAE) with tellurium chemistry.The advantages of the tellurium process are as follows: (1) the 50percent yield limitation on the allylic alcohol in the Sharpless kinetic resolution (SKR) can be overcome; (2) allylic tertiary alcohols which are unsatisfactory substrates in the SKR can be obtained in high optical purity; (3) optically active secondary allylic alcohols with tertiary alkyl substituents (e.g. tert-butyl) at C-1 can be obtained in high ee; (4) optically active sterically congested cis secondary alcohols can be obtained in high ee; and (5) the nuisance of the slow SAE of some vinyl carbinols can be avoided.The key step in the reaction sequence is either a stereospecific 1,3-transposition of double bond and alcohol functionalities or an inversion of the alcohol configuration with concomitant deoxygenation of the epoxide function in epoxy alcohols.Trans secondary allylic alcohols can be converted to cis secondary allylic alcohols by way of erythro epoxy alcohols (glycidols); threo glycidyl derivatives are converted to trans secondary allylic alcohols.These transformations are accomplished by the action of telluride ion, generated in situ from the element, on a glycidyl sulfonate ester.Reduction of elemental Te is conveniently done with rongalite (HOCH2SO2Na) in an aqueous medium.This method is satisfactory when Te2- is required to attack at primary carbon site of a glycidyl sulfonate.In cases where Te2- is required to attack a secondary carbon site, reduction of the tellurium must be done with NaBH4 or LiEt3BH.Elemental tellurium is precipitated during the course of the reactions and can be recovered and reused.
- Dittmer, Donald C.,Discordia, Robert P.,Zhang, Yanzhi,Murphy, Christopher K.,Kumar, Archana,et al.
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p. 718 - 731
(2007/10/02)
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- A Novel Carbon-Carbon Bond-Forming Reaction of Triflates with Copper(I)-Catalyzed Grignard reagents. A New Concise and Enantiospecific Synthesis of (+)-exo-Brevicomin, (5R,6S)-(-)-6-Acetoxy-5-hexadecanolide, and L-Factor
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We describe here a full accound of a highly concise and enantiospecific synthesis of (+)-exo-brevicomin (7), (5R,6S)-(-)-6-acetoxy-5-hexadecanolide (11), and L-factor (16) originating from D- or L-tartrates as chiral sources.The synthesis employs an effic
- Kotsuki, Hiyoshizo,Kadota, Isao,Ochi, Masamitsu
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p. 4417 - 4422
(2007/10/02)
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- A Facile Synthesis of (R)-1-Benzyloxy-3-buten-2-ol
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A functionalized optically active allyl alcohol, (R)-1-benzyloxy-3-buten-2-ol, is efficiently prepared from (S)-O-benzylglycidol in two steps.
- Takano, Seiichi,Tomita, Shun'ichi,Iwabuchi, Yoshiharu,Ogasawara, Kunio
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p. 610 - 611
(2007/10/02)
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- A Practical Synthesis of Several Polyhydroxylated Chiral Building Blocks
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A practical method for the synthesis of several useful polyhydroxylated chiral building blocks has been developed.The key reaction is the kinetic resolution of (E)-1-trimethylsilyl-4-alkoxy-1-buten-3-ol or (E)-1-trimethylsilyl-5-alkoxy-1-penten-3-ol using the Sharpless asymmetric epoxidation reaction.
- Kusakabe, Masato,Kato, Hiroshi,Sato, Fumie
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p. 2163 - 2166
(2007/10/02)
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A general method for the synthesis of chiral epoxides starting from the bifunctionalised epoxide synthon 2is described. This approach is useful for the preparation of saturated epoxides. β,γ - unsaturated analogues could not be easily obtained. In this case, the use of metallic acetylides with BF3. (C2H5)2O proved very helpful.
- Soulie,Lampilas,Lallemand
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p. 2701 - 2708
(2007/10/02)
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- SYNTHESIS OF (R)-1-BENZYLOXY-3-BUTEN-2-OL- A POTENTIAL CHIRAL SYNTHON FROM L-(+)-TARTARIC ACID: ITS APPLICATIONS IN NATURAL PRODUCT SYNTHESES
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A practical synthesis of (R)-3-butene-1,2-diol derivatives from (R,R)-tartaric acid and their applications for the syntheses of (R)-ethyl-5-benzoyloxy-5-formyl pentanoate (2), a useful synthon for the preparation of arachidonic acid metabolites and (R)-γ-caprolactone (3), a pheromone of Trogoderma species, are described.
- Rao, Rama A V,Reddy, E Rajathnam,Joshi, Bhalchandra V,Yadav, J S
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p. 6497 - 6500
(2007/10/02)
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- Total synthesis of (+)-colletodiol from (S,S)-tartrate and (R)-3-hydroxybutanoate
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The macrodiolide antibiotic (+)-colletodiol (7, Scheme 1) was synthesised.The configuration was thus proven to be (6R,11R,12R,14R). - Key intermediates (Schemes 9 and 10) are the two hydroxy acids 43 and 64, which were prepared from dimethyl (S,S)-tartrate in 20percent overall yield (12 steps) and from (R)-3-hydroxybutanoate in 57percent overall yield (6 steps), respectively.The two hydroxy acids were cyclised to give, after deprotection, the title compound. - Our investigations led to the production of a large number of chiral building blocks, many of them in different stereoisomeric forms.
- Schnurrenberger, Peter,Hungerbuehler, Ernst,Seebach, Dieter
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p. 733 - 744
(2007/10/02)
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- STUDIES ON THE SYNTHESIS OF THE APLYSIATOXINS: SYNTHESIS OF A SELECTIVELY-PROTECTED FORM OF THE C27-C30 (DIHYDROXYBUTANOATE) MOIETY OF OSCILLATOXIN A
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A protected form of (R)-3,4-dihydroxybutanoic acid bearing a benzyl protecting group at the C4 hydroxyl and a dimethylthexylsilyl protecting group at the C3 hydroxyl was synthesized via a selective Ag(I)-mediated monobenzylation of (R)-methyl 3,4-dihydroxybutanoate.An alternative synthetic route from a chiral allylic ether was successful but problematic.The acid could be clenly coupled to a model for the C3-C11 moiety of the aplysiatoxins.
- Walkup, Robert D.,Cunningham, Raymond T.
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p. 4019 - 4022
(2007/10/02)
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