Chemistry of oxaziridines. 16. A short, highly enantioselective synthesis of the AB-ring segments of .gamma.-rhodomycionone and .alpha.-citromycinone using (+)-[(8,8-dimethoxycamphoryl)sulfonyl]oxaziridine

Davis, Franklin A.; Kumar, Anil; Chen, Bang Chi

doi:10.1021/jo00003a042

Cited by 47 publications

(11 citation statements)

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“…Methylenation49 and exposure of the enol ether to Me 2 AlCl led via Petasis-Ferrier rearrangement to pyranone (−)- 114 as a single isomer. After considerable experimentation, introduction of the C(42) hydroxyl was achieved by treatment of the potassium enolate of (−)- 114 with the Davis oxaziridine (+)- 115 50 to provide alcohol (+)- 116 in good yield after epimerization of the C(40) methyl substituent. Silylation of the newly generated hydroxyl was then followed by selective axial-reduction and desilylation to furnish diol (+)- 117 , which was converted to F -ring aldehyde (+)- 108 in three additional steps: diol protection, removal of the p- methoxyphenyl (PMP) group, and oxidation.…”

Section: Resultsmentioning

confidence: 99%

Spongipyran synthetic studies. Evolution of a scalable total synthesis of (+)-spongistatin 1

Smith¹,

Sfouggatakis²,

Risatti³

et al. 2009

Tetrahedron

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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 one gram 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 mgs 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.

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Section: Resultsmentioning

confidence: 99%

Spongipyran synthetic studies. Evolution of a scalable total synthesis of (+)-spongistatin 1

Smith¹,

Sfouggatakis²,

Risatti³

et al. 2009

Tetrahedron

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“…6 It has been demonstrated that diastereoselective hydroxylation of chiral imide enolates with oxaziridine oxidants provides a convenient method for the preparation of R-hydroxy acid synthons (Scheme 102). 403,[465][466][467][468][469][470][471][472][473] Peroxydicarbonate can also be used as the oxidant. 474 The Michael addition of a carbon nucleophile followed by oxidation of the resultant enolate allows for the diastereoselective introduction of two groups.…”

Section: Alkylationsmentioning

confidence: 99%

“…α-Hydroxy acids, and simple derivatives thereof, have proven to be a versatile class of molecules that have been extensively exploited in asymmetric synthesis . It has been demonstrated that diastereoselective hydroxylation of chiral imide enolates with oxaziridine oxidants provides a convenient method for the preparation of α-hydroxy acid synthons (Scheme ). ,− Peroxydicarbonate can also be used as the oxidant 102 …”

Section: Oxygenationmentioning

confidence: 99%

1,2-Amino Alcohols and Their Heterocyclic Derivatives as Chiral Auxiliaries in Asymmetric Synthesis

1996

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“…CO 2 was purchased from Air Liquid. Camphorsulphonyl chloride (CS-Cl) was purchased from Fluka and the camphor compounds CCA-H, CCA-Li, 39 isonitrosocamphor (CI-OH) 40 and 3-oxocamphor-sulfonimide (CSI) 41,42 were prepared according to published procedures.…”

Section: Synthesis Of Camphor Compoundsmentioning

confidence: 99%

“…7) were purchased (CSI) or synthesized according to published procedures (see below). [39][40][41][42] The synthesized compounds are paradigms of the ligands tested in the docking studies: CC-NLi represents scaffolds 7 and 10, CSI corresponds to scaffold 4 with R 1 ¼ R 2 ¼ H, CI-OH corresponds to scaffold 1 with R 1 ¼ R 2 ¼ H, CC-NH is the nonlithiated version of CC-NLi, and C-phenaz represents scaffolds 8 and 9, which are two of the scaffolds with a higher correlation to a stronger binding ability. Besides these, CCA-H, the precursor of the synthetic pathways used, and CS-Cl, a simpler analogue of scaffold 4, were also tested.…”

Section: Synthetic Approachmentioning

confidence: 99%

Camphor-based CCR5 blocker lead compounds – a computational and experimental approach

et al. 2016

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The C-C chemokine receptor type 5 (CCR5) is a transmembrane receptor that plays a pivotal role as a HIV anchor to human cell membranes, mediating viral entry. CCR5 antagonists, acting by blocking the receptor and preventing its interaction with the HIV proteins, are key agents towards effective anti-viral therapy. This work describes the computational study, synthesis and viral inhibition assay of a number of camphor derivatives as a first step towards new drug leads to block this specific entry pathway. Viral inhibition assays have identified three molecules, camphor carboxylic acid, its tri(hydroxymethyl)aminomethane amide derivative, and an hydroxyl-imide camphor derivative as promising agents to develop new drugs, with IC 50 values (0.16, 0.22 and 1.02 mM, respectively) one order below that of maraviroc (0.02 mM), a clinically used CCR5 antagonist.

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Chemistry of oxaziridines. 16. A short, highly enantioselective synthesis of the AB-ring segments of .gamma.-rhodomycionone and .alpha.-citromycinone using (+)-[(8,8-dimethoxycamphoryl)sulfonyl]oxaziridine

Cited by 47 publications

References 0 publications

Spongipyran synthetic studies. Evolution of a scalable total synthesis of (+)-spongistatin 1

Spongipyran synthetic studies. Evolution of a scalable total synthesis of (+)-spongistatin 1

1,2-Amino Alcohols and Their Heterocyclic Derivatives as Chiral Auxiliaries in Asymmetric Synthesis

Camphor-based CCR5 blocker lead compounds – a computational and experimental approach

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