- Double diastereoselection in asymmetric [2+3] cycloaddition of chiral oxazoline N-oxides: Application to the kinetic resolution of a racemic α,β-unsaturated δ-lactone
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The asymmetric [2+3] cycloaddition reaction between chiral oxazoline N-oxide 1 and α,β-unsaturated lactone 2 was studied. A double diastereoselection was observed, (1R)-1 and (R)-2 gave a mismatched pair with almost no cycloadduct obtained. A transition state model is proposed, accounting for the destabilization of transition state in the cycloaddition reaction. This result has led to kinetic resolution studies, in which both enantiomers of 1 were reacted with racemic lactone 2. The enantiomeric excess of the recovered lactone 2 was determined to be up to 70% ee, by 13C-{1H} NMR analysis in a chiral liquid crystalline solvent. The experimental results are in agreement with predicted enantiomeric excesses and consistent with the transition state models.
- Dirat, Olivier,Kouklovsky, Cyrille,Langlois, Yves,Lesot, Philippe,Courtieu, Jacques
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Read Online
- Synthesis of (+)-spirolaxine methyl ether
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A short and efficient synthesis of (+)-spirolaxine methyl ether, a metabolite of the fungus Sporotrichum laxum with inhibitory activity against Helicobacter pylori, is described. The synthesis has been carried out by a Prins cyclization, to obtain the [6,
- Nannei, Raffaella,Dallavalle, Sabrina,Merlini, Lucio,Bava, Adriana,Nasini, Gianluca
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Read Online
- Convergent total synthesis of (±) myricanol, a cyclic natural diarylheptanoid
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Myricanol 1, a constituent of Myrica species, has been reported to lower the levels of the microtubule-associated protein tau (MAPT), whose accumulation plays an important role in some neurodegenerative diseases, such as Alzheimer's disease (AD). Herein w
- Bochicchio,Schiavo,Chiummiento,Lupattelli,Funicello,Hanquet,Choppin,Colobert
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p. 8859 - 8869
(2018/11/30)
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- Approach to the Core Structure of 15- epi -Exiguolide
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The synthesis of seco acid 41 of the macrolactone part of 15- epi -exiguolide, containing a bis-pyran subunit and a trans double bond, is described. Key features of the synthetic strategy include a Feringa-Minnaard asymmetric organocuprate addition to uns
- Riefert, Alexander,Maier, Martin E.
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p. 3131 - 3145
(2018/08/17)
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- Studies on C18-C20 aldol couplings of rhizopodin
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The aldol addition of an enol(ate) to a carbonyl compound is one of the most powerful and versatile C-C bond forming reactions. In complex target synthesis the coupling of two chiral partners may complicate the stereochemical outcome by multiple stereoinductions. Here, we report studies on pivotal aldol couplings employed in the rhizopodin synthesis, detailing the various directing effects exerted by the stereogenic centers present in this sterically hindered connection. Georg Thieme Verlag Stuttgart. New York.
- Dieckmann, Michael,Rudolph, Sven,Lang, Carolin,Ahlbrecht, Wiebke,Menche, Dirk
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p. 2305 - 2315
(2013/09/02)
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- Structural variants of mycolactones for use in modulating inflammation, immunity and pain
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The present invention is related to variants of mycolactones of formula (I), processes for the preparation thereof, pharmaceutical compositions thereof and their use in modulating inflammation, immunity and pain. ???????? Y-O-W?????(I) wherein Y and W are as defined in claim 1.
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Paragraph 0110-0113
(2013/06/05)
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- An efficient total synthesis of (-)-epothilone B
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An efficient total synthesis of (-)-epothilone B has been achieved in ca. 8% yield over 11 steps from 9 (or 10 steps from 7/8), which features a bissiloxane-tethered ring closing metathesis reaction to approach the trisubstituted (Z) double bond and forms a new basis for further development of an industrial process for epothilone B and ixabepilone.
- Wang, Jie,Sun, Bing-Feng,Cui, Kai,Lin, Guo-Qiang
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supporting information
p. 6354 - 6357
(2013/02/23)
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- Direct synthesis of B-allyl and B-allenyldiisopinocampheylborane reagents using allyl or propargyl halides and indium metal under Barbier-type conditions
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We report the first one-pot process for the asymmetric addition of allyl, methallyl, and propargyl groups to aldehydes and ketones using B-chlorodiisopinocampheylborane (dDIP-Cl) and indium metal. Under Barbier-type conditions, indium metal was
- Hirayama, Lacie C.,Haddad, Terra D.,Oliver, Allen G.,Singaram, Bakthan
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supporting information; experimental part
p. 4342 - 4353
(2012/06/30)
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- Syntheses of (-)-cryptocaryolone and (-)-cryptocaryolone diacetate via a diastereoselective oxy-Michael addition and oxocarbenium allylation
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The total syntheses of both (-)-cryptocaryolone and (-)-cryptocaryolone diacetate is presented herein. The usage of a diastereoselective oxy-Michael addition/benzylidene acetal formation coupled with a selective axial oxocarbenium allylation allowed for the preparation of the α-C-glycoside moiety present in the bicyclic bridged structure. In addition, the syn-1,3-diol of the linear portion was installed via a Wacker oxidation followed by a subsequent directed reduction of the appropriate homoallylic alcohol precursor.
- Albury, Aymara M. M.,Jennings, Michael P.
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experimental part
p. 6929 - 6936
(2012/10/08)
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- Sequencing cross-metathesis and non-metathesis reactions to rapidly access building blocks for synthesis
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The olefin cross-metathesis reaction has been sequenced with four common organic transformations in a one- or two-pot manner to rapidly access useful building blocks. Those reactions are: (1) phosphorus-based olefination (e.g., Wittig and Horner-Wadsworth-Emmons); (2) hydride reduction; (3) Evans propionate aldol reaction; (4) Brown allyl- and Roush crotyl-boration. The products of these reactions include stereodefined 2,4-dienoates, trans allylic alcohols, syn-propionate aldols, and chiral non-racemic homoallylic alcohols, respectively. Many of these intermediates have been carried further to natural products, demonstrating the utility of the methodology.
- Sirasani, Gopal,Paul, Tapas,Andrade, Rodrigo B.
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experimental part
p. 2197 - 2205
(2011/04/22)
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- Design and synthesis of pironetin analogues with simplified structure and study of their interactions with microtubules
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The preparation of a series of pironetin analogues with simplified structure is described. Their cytotoxic activity and their interactions with tubulin have been investigated. It has been found that, while less active than the parent molecule, the pironetin analogues still share the mechanism of action of the latter and compete for the same binding site to α-tubulin. Variations in the configurations of their stereocenters do not translate into relevant differences between biological activities.
- Marco, J. Alberto,García-Pla, Jorge,Carda, Miguel,Murga, Juan,Falomir, Eva,Trigili, Chiara,Notararigo, Sara,Díaz, J. Fernando,Barasoain, Isabel
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supporting information; experimental part
p. 1630 - 1637
(2011/05/06)
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- Enantio- and diastereoselective synthesis of (E)-1,5-syn-diols: Application to the synthesis of the C(23)-C(40) fragment of tetrafibricin
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A highly stereoselective synthesis of (E)-1,5-syn-diols 6 is described. The kinetically controlled hydroboration of allenyltrifluoroborate 8 with Soderquist borane 2 provides the (Z)-allylic trifluoroborate 9, which undergoes sequential allylboration with two different aldehydes to provide (E)-1,5-syn-diols 6 in 72-98% yields with >95% ee and >20:1 dr. Application of this method to the synthesis of the tetrafibricin C(23)-C(40) fragment 19 is described.
- Kister, Jeremy,Nuhant, Philippe,Lira, Ricardo,Sorg, Achim,Roush, William R.
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supporting information; experimental part
p. 1868 - 1871
(2011/06/22)
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- A stereoselective formal synthesis of leucascandrolide A
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A stereoselective formal synthesis of leucascandrolide A was accomplished through the tandem and organocatalytic oxa-Michael reactions, which were promoted by the gem-disubstituent effect, in conjunction with the dithiane coupling reaction.
- Lee, Kiyoun,Kim, Hyoungsu,Hong, Jiyong
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supporting information; experimental part
p. 2722 - 2725
(2011/06/28)
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- Formal synthesis of schulzeines B and C
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A formal synthesis of schulzeines B and C, marine natural products with inhibitory effect against α-glucosidase, has been achieved. The key reactions of the synthesis are N-acyliminium ion cyclization, Sharpless asymmetric dihydroxylation, olefin cross me
- Kuntiyong, Punlop,Akkarasamiyo, Sunisa,Piboonsrinakara, Nuanpan,Hemmara, Chitlada,Songthammawat, Poramate
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experimental part
p. 8034 - 8040
(2011/11/06)
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- Synthesis and biological activity of new functionalized epothilones for prodrug design and tumor targeting
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Epothilones are potent antiproliferative agents, which have served as successful lead structures for anticancer drug discovery. However, their therapeutic efficacy would benefit greatly from an increase in their selectivity for tumor cells, which may be a
- Dietrich, Silvia Anthoine,Riediker, Linda,Gertsch, Juerg,Altmann, Karl-Heinz
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scheme or table
p. 136 - 139
(2011/07/31)
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- Formal synthesis of (-)-Neopeltolide featuring a highly stereoselective oxocarbenium formation/reduction sequence
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The formal synthesis of the unnatural (-)-neopeltolide core is discussed in detail. Efficient application of the Evans protocol for the synthesis of 1,3-syn-diols via an intramolecular hetero-Michael addition followed by reductive deprotection of the resulting benzylidene acetal allowed for swift access to the δ-lactone. Central to the synthetic approach is a tandem nucleophilic addition-diastereoselective axial reduction of an in situ generated oxocarbenium cation to assemble the β-C-glycoside moiety of the neopeltolide core.
- Martinez-Solorio, Dionicio,Jennings, Michael P.
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experimental part
p. 4095 - 4104
(2010/09/11)
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- BRYOSTATIN ANALOGUES, SYNTHETIC METHODS AND USES
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Biologically active compounds related to the bryostatin family of compounds, having simplified spacer domains and/or improved recognition domains are disclosed, including methods of preparing and utilizing the same.
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Page/Page column 88-89; 90-94; 129
(2009/05/28)
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- BRYOSTATIN ANALOGUES, SYNTHETIC METHODS AND USES
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Biologically active compounds related to the bryostatin family of compounds, including methods of utilizing the same.
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Page/Page column 62-63
(2009/10/31)
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- Total synthesis of etnangien
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(Chemical Equation Presented) The first total synthesis of the potent RNA-polymerase inhibitor etnangien is described, which establishes unequivocally the relative and absolute configuration of this sensitive macrolide antibiotic. Key features of the expe
- Li, Pengfei,Li, Jun,Arikan, Fatih,Ahlbrecht, Wiebke,Dieckmann, Michael,Menche, Dirk
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supporting information; experimental part
p. 11678 - 11679
(2009/12/08)
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- Total synthesis of (+)-neopeltolide by a Prins macrocyclization
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(Chemical Equation Presented) Rings within rings: The total synthesis of (+)-neopeltolide was accomplished by employing an intramolecular Prins macrocyclization of an aldehydic homoallylic alcohol intermediate (see scheme).
- Woo, Sang Kook,Kwon, Min Sang,Lee, Eun
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p. 3242 - 3244
(2008/12/23)
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- Alteration of the bis-tetrahydrofuran core stereochemistries in asimicin can affect the cytotoxicity
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A systematic analysis using 10 synthetic asimicin stereoisomers revealed that the stereochemistry of the bis-tetrahydrofuran core, including the tetrahydrofuran rings and the adjacent hydroxy functions, had significant effect on its cytotoxicity. Our findings set to rest the highly controversial perception that the stereochemistry of the tetrahydrofuran core has little effect on the activity, which is not true for its cytotoxic effect, and also reinforces the previous conclusion that asimicin is a highly potent anticancer compound.
- Sinha, Subhash C.,Chen, Zhiyong,Huang, Zheng-Zheng,Nakamaru-Ogiso, Eiko,Pietraszkiewicz, Halina,Edelstein, Matthew,Valeriote, Frederick
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supporting information; experimental part
p. 7045 - 7048
(2009/11/30)
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- Total synthesis of hypermodified epothilone analogs with potent in vitro antitumor activity
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The convergent total synthesis of hypermodified epothilone analogs 1 and 2 has been achieved with the stereoselective cyclopropanation of allylic alcohol 17 and ring-closing olefin metathesis with diene 22 as the key steps. In spite of significant structural differences between these analogs and the natural epothilone scaffold, 1 and 2 are potent inducers of tubulin polymerization and inhibit the growth of human cancer cells in vitro with sub-nM IC50 values.
- Kuzniewski, Christian N.,Gertsch, Jurg,Wartmann, Markus,Altmann, Karl-Heinz
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supporting information; experimental part
p. 1183 - 1186
(2009/04/06)
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- STABLE BORANE REAGENTS AND METHODS FOR THEIR USE
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The invention provides methods for storing boranes (e.g. B-allyldiisopinocampheylborane). The invention also provides stable compositions comprising boranes, as well as methods for carrying out allylboration at high temperature and/or in the presence of w
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Page/Page column 4
(2008/12/09)
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- Enantioselective total synthesis of peloruside a: A potent microtubule stabilizer
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An enantioselective total synthesis of (+)-peloruside A (1) is described. Peloruside A (1) is a potent microtubule stabilizer with significant clinical potential. The synthesis is convergent and involves the assembly of C1-C10 segment 2 and C11-C24 segment 3 by a novel aldol protocol followed by Yamaguchi macrolactonization of the resulting seco-acid, selective methylation of hemi-ketal and removal of the protecting groups to peloruside A.
- Ghosh, Arun K.,Xu, Xiaoming,Kim, Jae-Hun,Xu, Chun-Xiao
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supporting information; experimental part
p. 1001 - 1004
(2009/04/07)
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- Asymmetrie total syntheses of two phlegmarine-type alkaloids, lycoposerramines-V and -W, newly isolated from lycopodium serratum
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Two new Phlegmarine-type alkaloids, lycoposerramines-V and -W, were isolated from Lycopodium serratum, and their structures including the absolute configuration were established by asymmetric total synthesis involving such key steps as Johnson-Claisen rea
- Shigeyama, Takahide,Katakawa, Kazuaki,Kogure, Noriyuki,Kitajima, Mariko,Takayama, Hiromitsu
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p. 4069 - 4072
(2008/02/11)
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- The total synthesis and biological properties of the cytotoxic macrolide FD-891 and its non-natural (Z)-C12 isomer
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A total, stereoselective synthesis of the naturally occurring, cytotoxic macrolide FD-891 and of its non-natural (Z)-C12 isomer is described. Three fragments of the main carbon chain were stereoselectively prepared by using asymmetric aldol and allylation reactions as the key steps. The molecule was then assembled by using two Julia-Kocienski olefinations to connect the three fragments and a Yamaguchi reaction to close the macrolactone ring. Some specific biological properties (cytotoxicity, binding to tubulin) have been determined for both macrolides. The E configuration of the C12-C13 olefinic bond seems to be an important feature in determining the cytotoxicity but the precise biological mechanism of the latter still remains to be cleared.
- Garcia-Fortanet, Jorge,Murga, Juan,Carda, Miguel,Marco, J. Alberto,Matesanz, Ruth,Diaz, J. Fernando,Barasoain, Isabel
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p. 5060 - 5074
(2008/02/11)
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- Competitive cationic pathways and the asymmetric synthesis of aryl-substituted cyclopropanes
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Equation presented 1,2-Disubstituted cyclopropanes were synthesized in a nonracemic fashion via activation of the corresponding homoallylic alcohols in excellent yields. A series of substituted phenyl rings showed higher enantiospecificity for the cyclization as the electron-withdrawing ability of the group increased. The results offer strong support for the existence of competing cation mechanisms.
- Melancon, Bruce J.,Perl, Nicholas R.,Taylor, Richard E.
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p. 1425 - 1428
(2008/02/03)
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- Convenient synthesis of stable aldimine - Borane complexes, chiral δ-amino alcohols, and γ-substituted GABA analogues from nitriles
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A one-pot synthesis of stable aldimine-trialkylborane adducts, the first synthesis of C- and N-deuterated imine-borane complexes, and their application for a highly enantioselective (84-99% ee) synthesis of δ-amino alcohols and γ-substituted γ-aminobutyri
- Ramachandran, P. Veeraraghavan,Biswas, Debanjan
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p. 3025 - 3027
(2008/02/10)
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- Total synthesis of marinomycins A-C and of their monomeric counterparts monomarinomycin A and iso-monomarinomycin A
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Marinomycins A-C (1-3), and their monomeric analogues monomarinomycin A (m-1) and iso-monomarinomycin A (m-2), were synthesized by a convergent strategy from key building blocks ketophosphonate 5, aldehyde 6, and dienyl bromide carboxylic acid 7. The first attempt to construct marinomycin A [1, convertible to marinomycins B (2) and C (3) by light] by direct Suzuki-type dimerization/ cyclization of boronic acid dienyl bromide 4 led to premature ring closure to afford, after global desilylation, monomarinomycin A (m-1) and iso-monomarinomycin A (m-2) in good yield and only small amounts (≤2%) of the desired product. A subsequent stepwise approach based on Suzuki-type couplings improved considerably the overall yield of marinomycin A (1), and hence of marinomycins B (2) and C (3). Alternative direct dimerization approaches based on the Stille and Heck coupling reactions also led to monomarinomycins A (m-1 and m-2), but failed to deliver useful amounts of marinomycin A (1).
- Nicolaou,Nold, Andrea L.,Milburn, Robert R.,Schindler, Corinna S.,Cole, Kevin P.,Yamaguchi, Junichiro
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p. 1760 - 1768
(2007/10/03)
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- Enantioselective synthesis and absolute configurations of aculeatins A, B, D, and 6-epi-aculeatin D
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The three naturally occurring, bioactive spiroacetals aculeatins A, B, and D, as well as the non-natural 6-epi-aculeatin D have been synthesized for the first time in enantiopure form using an asymmetric allylation as the only chirality source. A further
- álvarez-Bercedo, Paula,Falomir, Eva,Carda, Miguel,Marco
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p. 9641 - 9649
(2007/10/03)
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- Antiparasite and antimycobacterial activity of passifloricin analogues
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Several structural analogues of the polyketide passifloricin lactone were synthesized using asymmetric stereoselective allylations and ring-closing methateses as key reactions. These compounds were active in vitro against intracellular amastigotes of Leishmania panamensis (strain UA140), trophozoites of Plasmodium falciparum (strain NF54), and Mycobacterium tuberculosis (strain H37Rv). However, in spite of the significative antiparasitic activity of some synthetic analogues a high cytotoxicity was also observed. Based on these results a lactam derivative was also synthesized. This compound maintained a good level of activity with less toxicity.
- Cardona, Wilson,Qui?ones, Winston,Robledo, Sara,Vélez, Ivan Darío,Murga, Juan,García-Fortanet, Jorge,Carda, Miguel,Cardona, Diana,Echeverri, Fernando
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p. 4086 - 4092
(2007/10/03)
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- Design, total synthesis, and evaluation of novel open-chain epothilone analogues
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The design, total synthesis, and biological evaluation of two open-chain analogues of epothilone incorporating the critical C1-C8 fragment and the aromatic side chain held together by a small molecular scaffold have been achieved. Biological evaluation revealed that further restraint between the flexible C1-C8 region and the molecular scaffold may be necessary for potent inhibition of cell proliferation.
- Alhamadsheh, Mamoun M.,Hudson, Richard A.,Tillekeratne, L. M. Viranga
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p. 685 - 688
(2007/10/03)
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- Stereoselective synthesis of the monomeric unit of SCH 351448
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The monomeric unit of the macrodiolide SCH 351448 has been synthesized from three building blocks. Strategic disconnections were chosen between C21-C22 (Wittig) and C10-C11 (stereoselective aldol). The cis configuration of both 2,6-disubstituted tetrahydropyran rings was established by a stereoselective cationic reduction. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Backes, J. Rene,Koert, Ulrich
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p. 2777 - 2785
(2007/10/03)
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- A new route to trans-2,6-disubstituted piperidine-related alkaloids using a novel C2-symmetric 2,6-diallylpiperidine carboxylic acid methyl ester
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A novel C2-symmetric 2,6-diallylpiperidine carboxylic acid methyl ester 1 was prepared by the double asymmetric allylboration of glutaldehyde followed by an aminocyclization and carbamation. On the basis of desymmetrization of 1 using iodocarbamation, one allyl group of 1 was protected and monofunctionalizations of the resulting oxazolidinone 11 were performed. The reaction of the N-methoxycarbonyl piperidine 25 employing decarbamation reagent (n-PrSLi or TMSI) as a key step gave oxazolidinone 26 or 17 including an intramolecular ring formation, which was transformed in a few steps into (-)-porantheridine (2) and (-)-2-epi-porantheridine (3), respectively. In addition, the expedient synthesis of (+)-epi-dihydropinidine (4), (2R,6R)-trans-solenopsin A (5), and precoccinelline (6), starting from 11 is described. The Royal Society of Chemistry 2006.
- Takahata, Hiroki,Saito, Yukako,Ichinose, Motohiro
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p. 1587 - 1595
(2008/02/03)
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- Synthesis of iso-epoxy-amphidinolide N and des-epoxy-caribenolide i structures. Initial forays
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Two strategies for the projected total synthesis of the phenomenally potent antitumour macrolides amphidinolide N (1) and caribenolide I (2) are described. The title compounds are introduced as challenging and unique targets for chemical synthesis, and their retrosynthetic analysis is presented. The synthesis of the four defined key building blocks (10, 39, 67 and 72), required for the construction of amphidinolide N (1), in their enantiomerically pure forms, is described, followed by the coupling of 10, 39 and 72 through hydrazone alkylation processes to generate the complete C6-C29 carbon framework of the target compound (1). Fusion of the remaining C1-C5 sector (72) onto the molecule by metathesis-based methods was unsuccessful, resulting in the adoption of a second-generation strategy which called for the employment of one of the array of palladium-catalysed cross-coupling reactions to generate the C5-C6 carbon-carbon bond. Vinyl bromide 125, representing the C6-C29 skeleton of caribenolide I (2), was prepared through the sequential alkylation of hydrazone 10 with bromide 116 and iodide 55, but failed to engage in the appropriate cross-coupling reaction with a variety of C1-C4 partners. Despite these setbacks, the information gleaned from these endeavours was to prove invaluable in laying the foundation for the eventual successful approach to the macrocyclic structures of amphidinolide N (1) and caribenolide I (2). The Royal Society of Chemistry 2006.
- Nicolaou,Brenzovich, William E.,Bulger, Paul G.,Francis, Tasha M.
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p. 2119 - 2157
(2008/02/07)
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- Stereoselective synthesis of the naturally occurring styryllactones (+)-goniofufurone and (+)-cardiobutanolide
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(Chemical Equation Presented) The naturally occurring γ-lactones (+)-goniofufurone 1 and (+)-cardiobutanolide 2, two pharmacologically active products from Goniothalamus species (Annonaceae), have been synthesized in enantiopure form using L-erythrulose a
- Ruiz, Purificacion,Murga, Juan,Carda, Miguel,Marco, J. Alberto
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p. 713 - 716
(2007/10/03)
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- Heterocyclic ring scaffolds as small-molecule cholesterol absorption inhibitors
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Enantio- and diastereoselective syntheses of a substituted oxazolidinone, isoxazoline and pyrazoline as β-lactam surrogates are described. The substituted heterocycles were designed to incorporate side chains closely resembling those found in the β-lactam cholesterol absorption inhibitor ezetimibe (1). Additionally, the in vitro inhibitory efficacy of the novel compounds as cholesterol absorption inhibitors is reported using a brush border membrane vesicle assay. The Royal Society of Chemistry 2005.
- Ritter, Tobias,Kvaerno, Lisbet,Werder, Moritz,Hauser, Helmut,Carreira, Erick M.
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p. 3514 - 3523
(2007/10/03)
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- Role of the A-ring of bryostatin analogues in PKC binding: Synthesis and initial biological evaluation of new A-ring-modified bryologs
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(Chemical Equation Presented) The syntheses of three newly designed bryostatin analogues are reported. These simplified analogues, which lack the A-ring present in the natural product but possess differing groups at C9, were obtained using a divergent app
- Wender, Paul A.,Clarke, Michael O.,Horan, Joshua C.
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p. 1995 - 1998
(2007/10/03)
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- The stereocontrolled total synthesis of altohyrtin A/spongistatin 1: The CD-spiroacetal segment
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Stereocontrolled syntheses of the C16-C28 CD-spiroacetal subunit of altohyrtin A/spongistatin 1 (1), relying on kinetic and thermodynamic control of the spiroacetal formation, are described. The kinetic control approach resulted in a slight preference (60: 40) for the desired spiroacetal isomer. The thermodynamic approach allowed ready access to the desired spiroacetal 2 by acid-promoted equilibration, Chromatographic separation of the C23 epimers and resubjection of the undesired isomer to the equilibration conditions. This scalable synthetic sequence provided multi-gram quantities of 2, thus enabling the successful completion of the total synthesis of altohyrtin A/spongistatin 1, as reported in Part 4 of this series. The Royal Society of Chemistry 2005.
- Paterson, Ian,Coster, Mark J.,Chen, David Y.-K.,Gibson, Karl R.,Wallace, Debra J.
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p. 2410 - 2419
(2007/10/03)
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- Total Synthesis of (-)-Apicularen A
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Complete details of an asymmetric synthesis of apicularen (1) are described. The synthesis has been accomplished using a highly diastereo- and enantioselective [4 + 2] annulation for the assembly of the functionalized pyran core. An underdeveloped lactoni
- Su, Qibin,Panek, James S.
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p. 2425 - 2430
(2007/10/03)
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- Synthesis and conformational analysis of macrocycles related to 10-oxa-epothilone
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A short and convergent synthesis of macrocyclic lactones related to 10-oxa-epothilone is based on aldolisation of a 3-(2′-methylallyloxy) aldehyde derived from methyl (2S)-3-hydroxy-2-methylpropionate followed by ring-closing metathesis. Wiley-VCH Verlag
- Quintard, Delphine,Bertrand, Philippe,Bachmann, Christian,Gesson, Jean-Pierre
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p. 4762 - 4770
(2007/10/03)
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- Synthesis of polyketides via diastereoselective acetalization
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(Matrix presented) Diastereoselective acetalization of pseudo-C 2-symmetric 1,3,5-triol systems is a general strategy for the rapid generation of polyketides. The oxidative acetalization reaction shown above was studied under both kinetic and t
- Shepherd, Jennifer N.,Myles, David C.
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p. 1027 - 1030
(2007/10/03)
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- Total synthesis of (+)-phorboxazole A, a potent cytostatic agent from the sponge Phorbas sp.
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A convergent total synthesis of phorboxazole A (1a), from the C(3-19), C(20-27) and C(33-46) fragments 5, 4 and 91, respectively, concentrating on stereocontrolled formation of the bonds at C(2-3), C(19-20) and C(27-28), is described. Although a coupling reaction between a macrolide ketone and the side chain substituted sulfone, at C(27-28) was not successful, a Wadsworth-Emmons olefination involving the oxane methyl ketone 4 and an oxazole produced the oxane 90 which was next coupled to 91 leading to the C(20-46) unit 100. A further coupling of 100 to 71c at C(19-20) then led to 105, ultimately, and the synthesis was completed by a macrocyclisation reaction from 105, at the C(2-3) alkene bond, followed by deprotection of 106.
- Pattenden, Gerald,Gonzalez, Miguel A,Little, Paul B,Millan, David S,Plowright, Alleyn T,Tornos, James A,Ye, Tao
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p. 4173 - 4208
(2007/10/03)
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- A novel C(2)-symmetric 2,6-diallylpiperidine carboxylic acid methyl ester as a promising chiral building block for piperidine-related alkaloids.
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C(2)-symmetric 2,6-diallylpiperidine 1-carboxylic acid methyl ester (5) was examined via the double asymmetric allylboration of glutaraldehyde followed by aminocyclization and carbamation as a promising chiral building block for piperidine-related alkaloids, which were synthesized by the desymmetrization of 5 using intramolecular iodocarbamation as a key step. [reaction: see text]
- Takahata, Hiroki,Ouchi, Hidekazu,Ichinose, Motohiro,Nemoto, Hideo
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p. 3459 - 3462
(2007/10/03)
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- Enantioselective allylation of β,γ-unsaturated aldehydes generated via Lewis acid induced rearrangement of 2-vinyloxiranes
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(matrix presented) 2-Vinyloxiranes have been found to be excellent surrogates to β,γ-unsaturated aldehydes. These valuable electrophiles, generated in situ by treatment of a 2-vinyloxirane with a catalytic amount of Sc(OTf)3, are effectively tr
- Lautens, Mark,Maddess, Matthew L.,Sauer, Effiette L. O.,Ouellet, Stephane G.
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- The synthesis of an exhaustively stereodiversified library of cis-1,5 enediols by silyl-tethered ring-closing metathesis.
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[reaction: see text] This report describes the parallel synthesis of all 16 stereoisomers of the cis-1,5 enediol module 1. Compounds 1 derive from 2 by silicon-tethered ring-closing metathesis. Such libraries of stereodiversified ligands provide a unique
- Harrison,Verdine
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p. 2157 - 2159
(2007/10/03)
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- Total synthesis of 16-desmethylepothilone B, epothilone B10, epothilone F, and related side chain modified epothilone B analogues
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The macrolactonization-based strategy for the total synthesis of epothilones has been streamlined and improved to a high level of efficiency and stereoselectivity. This strategy has been applied to the construction of vinyl iodide 19 which served as a com
- Nicolaou,Hepworth, David,King, N. Paul,Raymond,Finlay,Scarpelli, Rita,Manuela,Pereira,Bollbuck, Birgit,Bigot, Antony,Werschkun, Barbara,Winssinger, Nicolas
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p. 2783 - 2800
(2007/10/03)
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- Enantioselective synthesis of optically active homoallylamines by allylboration of N-diisobutylaluminum imines
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Diisobutylaluminum hydride (DIBAL-H) reduces nitriles to give N-diisobutylaluminum imines, which were asymmetrically allylated with chirally modified allylboron reagents. The corresponding chiral primary homoallylamines were obtained with up to 87% ee.
- Watanabe, Katsuhiro,Kuroda, Shizue,Yokoi, Ayako,Ito, Koichi,Itsuno, Shinichi
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p. 103 - 107
(2007/10/03)
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