Enantioselective Total Synthesis of Bistramide A

Crimmins, Michael T.; DeBaillie, Amy C.

doi:10.1021/ja057686l

Cited by 91 publications

(76 citation statements)

References 27 publications

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“…Epoxy alcohol 17 was prepared via Sharpless epoxidation 23 of allyl alcohol 16 as described by Crimmins and co-workers. 24 The epoxide was opened stereo- and regioselectively using Gilman’s methyl cuprate 25 at −50 °C to −10 °C followed by addition of NaIO 4 to give the corresponding 1,3-diol 18 in 76% yield. Chemoselective introduction of the 1-phenyl-1 H -tetrazol-5-yl (PT) sulfide provided thioether 19 , followed by silyl protection, resulted in sulfide 20 in 84% yield for the two-steps.…”

Section: Resultsmentioning

confidence: 99%

Enantioselective total synthesis and structural assignment of callyspongiolide

2016

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We have elucidated the complete absolute configuration of callyspongiolide and unambiguously assigned its stereochemistry at the C-21 center through synthesis. Four stereoisomers of callyspongiolide were synthesized in a convergent and enantioselective manner. A late-stage Sonogashira coupling forges the diene-ynic side chain. Other notable reactions are Yonemitsu’s variation of the Yamaguchi macrolactonization to cyclize an alkynic seco acid, highly trans-selective Julia-Kocienski olefination, CBS reduction to set the C-21 stereocenter, and methyl cuprate addition to an unsaturated pyranone to install the C-5 methyl center.

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Section: Resultsmentioning

confidence: 99%

Enantioselective total synthesis and structural assignment of callyspongiolide

2016

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“…Protected diol 7 13 was readily prepared from chiral epoxide 15 as described by Crimmins and co-workers. 13 Selective Mitsunobu displacement with 1-phenyl-1 H -tetrazole-5-thiol (PTSH, 16 ) followed by protection of the latent secondary alcohol provided sulfide 17 in 79% yield over two steps. Oxidation using m -chloroperbenzoic acid ( m -CPBA) afforded sulfone 18 .…”

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confidence: 99%

Enantioselective Synthesis of Both Epimers at C-21 in the Proposed Structure of Cytotoxic Macrolide Callyspongiolide

Ghosh

Kassekert

2016

Org. Lett.

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Both epimers at C-21 in the proposed structure of (+)-callyspongiolide have been synthesized in a convergent and enantioselective manner. The 14-membered macrolide with a sensitive C2–C3 cis-olefin functionality was installed by a Yamaguchi macrolactonization of hydroxyl alkynoic acid followed by hydrogenation over Lindlar’s catalyst. The C5 methyl stereocenter was constructed by a ring-closing olefin metathesis followed by addition of methyl cuprate to an α,β-unsaturated δ-lactone. Other key reactions are chiral Corey–Bakshi–Shibata (CBS) reduction and Sonogashira coupling to conjoin the macrocyclic core and side chain.

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“…For instance, phorboxazoles, [1] trehazolins, [2] allosamidins, [3] lasonolides, [4] spongistatins, [5] ambruticin, [6] bistramide A, [7] sorangicins, [8] monensins, [9] nigericin, [10] and the antibiotic Ro-21-6150, [11] all bear this structural feature as well as fascinating and important bioactivities ( Figure 1). For instance, phorboxazoles, [1] trehazolins, [2] allosamidins, [3] lasonolides, [4] spongistatins, [5] ambruticin, [6] bistramide A, [7] sorangicins, [8] monensins, [9] nigericin, [10] and the antibiotic Ro-21-6150, [11] all bear this structural feature as well as fascinating and important bioactivities ( Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Regio‐ and Stereoselective Synthesis of Acetallic Tetrahydropyrans as Building Blocks for Natural Products Preparation, via a Tandem [4+3]‐Cycloaddition/Ozonolysis Process

et al. 2016

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A highly versatile synthetic pathway is presented for the preparation of polyfunctionalized acetallic tetrahydropyrans from conveniently substituted 1‐methoxy‐8‐oxabicyclo[3.2.1]oct‐6‐en‐3‐one derivatives, as intermediates in the total synthesis of natural and unnatural products with structural, functional and/or biological importance. This synthetic methodology involves two key steps: a [4 + 3] cycloaddition reaction between an oxyallyl cation and 2‐methoxyfuran as a diene, followed by oxidative and/or reductive ozonolysis of the cycloheptenone subunit. This sequence renders polyfunctionalized 2‐methoxytetrahydropyranic products capable of being easily opened under acidic conditions. The key steps, cycloaddition and subsequent ozonolysis were both fully studied under different reaction conditions and using several substrates in order to optimize yields and stereoselectivities and to study the scope of the methodology. It is noteworthy that both reactions proceed with high diastereoselectivity and, in the case of the oxidative ozonolysis, outstanding regioselectivity as well. A chemical library of 14 polyfunctionalized tetrahydrofurans, having five or seven stereocenters, has been prepared using the detailed approach.

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Enantioselective Total Synthesis of Bistramide A

Cited by 91 publications

References 27 publications

Enantioselective total synthesis and structural assignment of callyspongiolide

Enantioselective total synthesis and structural assignment of callyspongiolide

Enantioselective Synthesis of Both Epimers at C-21 in the Proposed Structure of Cytotoxic Macrolide Callyspongiolide

Regio‐ and Stereoselective Synthesis of Acetallic Tetrahydropyrans as Building Blocks for Natural Products Preparation, via a Tandem [4+3]‐Cycloaddition/Ozonolysis Process

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