- Synthesis of the C9-C25 Subunit of Spirastrellolide B
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The synthesis of the C9-C25 subunit of the marine natural product spirastrellolide B is reported. The key synthetic features included the union of the two key fragments 5 and 6 via a Suzuki-Miyaura coupling reaction and a late-stage, one-pot sequential de
- Maitra, Soma,Bodugam, Mahipal,Javed, Salim,Hanson, Paul R.
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p. 3094 - 3097
(2016/07/13)
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- Synthetic Studies toward the C32-C46 Segment of Hemicalide. Assignment of the Relative Configuration of the C36-C42 Subunit
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The synthesis of five diastereomeric model compounds incorporating the C32-C46 segment of the antitumor marine natural product hemicalide has been achieved through a convergent approach relying on the 1,4-addition of an alkenyl boronate to an α,β-unsaturated δ-lactone followed by α-hydroxylation of an enolate and a Julia-Kocienski olefination. Comparison of the 1H and 13C NMR data of the model compounds with those of hemicalide enabled the assignment of the relative configuration of the C36-C42 subunit. (Chemical Equation Presented).
- Specklin, Simon,Boissonnat, Guillaume,Lecourt, Camille,Sorin, Geoffroy,Lannou, Marie-Isabelle,Ardisson, Janick,Sautel, Fran?ois,Massiot, Georges,Meyer, Christophe,Cossy, Janine
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supporting information
p. 2446 - 2449
(2015/05/27)
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- Chemoenzymatic Asymmetric Total Synthesis of Nonanolide (Z)-Cytospolides D, e and Their Stereoisomers
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Chemoenzymatic asymmetric total synthesis of the (Z)-isomer of the naturally occurring decanolide cytospolides D, E and six stereoisomers is reported. The main highlight of the synthetic venture involves ring-closing metathesis (RCM) reaction of a suitably functionalized ester compound, which was assembled by the Yamaguchi coupling of the required acid and alcohol fragments. The alcohol fragment was accessed by two alternative chemoenzymatic processes, one being hydroxynitrile lyase mediated hydrocyanation, whereas lipase-catalyzed transesterification was the key sep in the second route. The acid fragment was constructed by an enantioselective enzymatic desymmetrization (EED) of prochiral 2-methyl-1,3-propanediol and Corey-Bakshi-Shibata (CBS) mediated stereoselective carbonyl reduction.
- Rej, Rohan Kalyan,Nanda, Samik
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p. 860 - 871
(2015/10/05)
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- Spongipyran synthetic studies. Evolution of a scalable total synthesis of (+)-spongistatin 1
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Three syntheses of the architecturally complex, cytotoxic marine macrolide (+)-spongistatin 1 (1) are reported. Highlights of the first-generation synthesis include: use of a dithiane multicomponent linchpin coupling tactic for construction of the AB and CD spiroketals, and their union via a highly selective Evans boron-mediated aldol reaction en route to an ABCD aldehyde; introduction of the C(44)-C(51) side chain via a Lewis acid-mediated ring opening of a glucal epoxide with an allylstannane to assemble the EF subunit; and final fragment union via Wittig coupling of the ABCD and EF subunits to form the C(28)-C(29) olefin, followed by regioselective Yamaguchi macrolactonization and global deprotection. The second- and third-generation syntheses, designed with the goal of accessing 1 g of (+)-spongistatin 1 (1), maintain both the first-generation strategy for the ABCD aldehyde and final fragment union, while incorporating two more efficient approaches for construction of the EF Wittig salt. The latter combine the original chelation-controlled dithiane union of the E- and F-ring progenitors with application of a highly efficient cyanohydrin alkylation to append the F-ring side chain, in conjunction with two independent tactics to access the F-ring pyran. The first F-ring synthesis showcases a Petasis-Ferrier union/rearrangement protocol to access tetrahydropyrans, permitting the preparation of 750 mg of the EF Wittig salt, which in turn was converted to 80 mg of (+)-spongistatin 1, while the second F-ring strategy, incorporates an organocatalytic aldol reaction as the key construct, permitting completion of 1.009 g of totally synthetic (+)-spongistatin 1 (1). A brief analysis of the three syntheses alongside our earlier synthesis of (+)-spongistatin 2 is also presented.
- Smith III, Amos B.,Sfouggatakis, Chris,Risatti, Christina A.,Sperry, Jeffrey B.,Zhu, Wenyu,Doughty, Victoria A.,Tomioka, Takashi,Gotchev, Dimitar B.,Bennett, Clay S.,Sakamoto, Satoshi,Atasoylu, Onur,Shirakami, Shohei,Bauer, David,Takeuchi, Makoto,Koyanagi, Jyunichi,Sakamoto, Yasuharu
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supporting information; experimental part
p. 6489 - 6509
(2011/02/25)
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- Total synthesis of (-)-basiliskamide B
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The total synthesis of the polyketide antibiotic (-)-basiliskamide B is described. The convergent asymmetric synthesis relies on the use of a diastereoselective ethyl ketone aldol reaction followed by a syn selective reduction of a β-hydroxy ketone and a
- Dias, Luiz C.,Goncalves, Caroline Da Costa S.
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scheme or table
p. 1017 - 1021
(2009/05/27)
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- Synthetic studies toward cytostatin, a natural product inhibitor of protein phosphatase 2A
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Synthetic approaches toward the natural product cytostatin, an inhibitor of protein phosphatase 2A possessing cytotoxic and antimetastatic activities, have been investigated. A formal synthesis of cytostatin has been achieved according to a strategy relyi
- Salit, Anne-Frédérique,Meyer, Christophe,Cossy, Janine,Delouvrié, Bénédicte,Hennequin, Laurent
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p. 6684 - 6697
(2008/12/20)
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- SYNTHESIS OF DISCODERMOLIDE
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The invention relates to a process for preparing discodermolide, for preparing intermediates for the manufacture of discodermolide and discodermolide analogues and to the intermediates obtained during the process. Wherein the process proceeds via a tetrae
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- Spongistatin synthetic studies. An efficient, second-generation construction of an advanced ABCD intermediate
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(formula presented) A short, efficient, and stereocontrolled synthesis of (-)-4, an advanced ABCD subunit of the spongistatins, has been achieved. Central to the synthetic strategy is the multicomponent linchpin union of silyl dithianes with epoxides to access both the AB and CD fragments. Fragment coupling was then achieved via an efficient stereoselective aldol reaction. The linear sequence required 22 steps and proceeded in 4.0% overall yield.
- Smith III, Amos B.,Doughty, Victoria A.,Sfouggatakis, Chris,Bennett, Clay S.,Koyanagi, Jyunichi,Takeuchi, Makoto
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p. 783 - 786
(2007/10/03)
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- Toward the combinatorial synthesis of polyketide libraries: Asymmetric aldol reactions with α-chiral aldehydes on solid support
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(Matrix presented) The viability of performing stereocontrolled aldol additions with α-chiral aldehydes attached by a silyl linker to a hydroxymethylpolystyrene resin is demonstrated for boron and titanium enolates. Subsequent ketone reduction and manipul
- Paterson, Ian,Temal-Laib, Taoues
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p. 2473 - 2476
(2007/10/03)
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- A convergent three-component total synthesis of the powerful immunosuppressant (-)-sanglifehrin A
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The potent immunosuppressive agent (-)-sanglifehrin A (5), initially discovered in a soil sample from Malawi, has been synthesized in a highly conver soil gent and stereocontrolled manner. The enantioselective approach relies on initial construction of th
- Paquette, Leo A.,Duan, Maosheng,Konetzki, Ingo,Kempmann, Christoph
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p. 4257 - 4270
(2007/10/03)
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- A practical synthesis of (+)-discodermolide and analogues: Fragment union by complex aldol reactions
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A practical stereocontrolled synthesis of (+)-discodermolide (1) has been completed in 10.3% overall yield (23 steps longest linear sequence). The absolute stereochemistry of the C1-C6 (7), C9-C16 (8), and Csub
- Paterson,Florence,Gerlach,Scott,Sereinig
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p. 9535 - 9544
(2007/10/03)
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- Stereoselective synthesis of the C(1)-C(12) fragments of tedanolides - Application of a syn-selective tin(II)-mediated aldol reaction and a convertible methoxybenzyl protecting group
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Stereoselective synthesis of two C(1)-C(12) fragments, 3 and 4, of antitumor agents tedanolide (1) and 13-deoxytedanolide (2) was achieved by means of several regio- and/or stereoselective reactions. Ethyl ketone 14 was synthesized from methyl (S)-3-hydro
- Matsui, Katsuya,Zheng, Bao-Zhong,Kusaka, Shin-Ichi,Kuroda, Masaya,Yoshimoto, Katsuya,Yamada, Haruo,Yonemitsu, Osamu
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p. 3615 - 3624
(2007/10/03)
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- Total synthesis of (+)-crocacin C.
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The first asymmetric synthesis of (+)-crocacin C (3) is described which served to confirm the absolute configuration of this compound. The key step in the sequence was the stereoselective assembly of the (E,E)-diene amide side chain by a Stille cross-coup
- Feutrill,Lilly,Rizzacasa
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p. 3365 - 3367
(2007/10/03)
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- Anti aldol reactions of α-alkoxymethyl ketones: Application to the total synthesis of (+)-restricticin
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The antifungal agent (+)-restricticin (1) was prepared in 12 steps from ketone (S)-8. The key steps are (i) the boron-mediated anti aldol reaction of (S)-8 with 9 to give 13 and (ii) the cyclisation reaction 4 → 15.
- Paterson, Ian,Nowak, Thorsten
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p. 8243 - 8246
(2007/10/03)
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