Highly stereocontrolled total synthesis of the polyether antibiotic salinomycin. III. Total synthesis of salinomycin via coupling of C1-C9, C10-C17, and C-18-C30 segments.

Horita, Kiyoshi; Oikawa, Yuji; Nagato, Satoshi; Yonemitsu, Osamu

doi:10.1248/cpb.37.1717

Cited by 22 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because the crude product 13 could not be hydrogenated, it was treated with methanolic HCl to give the acetal 14 which was obtained as a single diastereomer, most likely having an ( R )-configured anomeric carbon. The hydrogenation of this substrate was still challenging, and thus different catalysts were investigated. The commonly employed Rh/Al 2 O 3 21a led to incomplete conversions as can be seen from the isolation of the tricyclic diacetal 16 as a side product after cyclization.…”

Section: Resultsmentioning

confidence: 99%

Comprehensive Study of Okaspirodiol: Characterization, Total Synthesis, and Biosynthesis of a New Metabolite fromStreptomyces

et al. 2006

View full text Add to dashboard Cite

The new spiro[4.5]acetal okaspirodiol (4) was isolated from Streptomyces sp. Gö TS 19 as a secondary metabolite in yields up to 380 mg/L. The structure of this cryptic ketotetrol was elucidated by different methods including X-ray analysis, and its equilibration under mildly acidic conditions furnishing three additional isomers was thoroughly studied. Although metabolite 4 is not the thermodynamically favored isomer, a high-yielding total synthesis was accomplished comprising a stereoselective spiroacetalization under equilibrium conditions. This approach benefits from the important influence of an intramolecular hydrogen bond on the stabilization of the spiro[4.5]acetal moiety. The biosynthesis of 4 was investigated by feeding experiments with 13C-labeled precursors proving its origin from a new type of the rare mixed acetate-glycerol biosynthetic pathway. All results are discussed on the basis of the structural diversity of spiroacetals in nature and their chemical properties.

show abstract

Section: Resultsmentioning

confidence: 99%

Comprehensive Study of Okaspirodiol: Characterization, Total Synthesis, and Biosynthesis of a New Metabolite fromStreptomyces

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Removal of the solvent at reduced pressure afforded a pale brown oil which was purified by flash chromatography with hexane-ethyl acetate (2 : 1) as eluent to give the title compound 17 (122 mg, 77%) as a colourless oil (Found: C, 60.6; H, 8.6. C 8 H 14 O 3 requires C, 60.7; H, 8.9%); [α] D Ϫ17.6 (c 1.7, CH 2 Cl 2 ); ν max (film)/cm Ϫ1 3640-3077 (br s, OH), 2973, 2937, 2882s (CH) and 1763s (C᎐ ᎐ O); δ H (200 MHz; CDCl 3 ) 0.94 (3H, t, J 7.5, CH 2 CH 3 ), 1.29 (3H, d, J 7.0, 3-Me), 1.69 (2H, q, J 7.5, CH 2 CH 3 ), 1.95 (1H, dd, J 4A,4B 12.9, J 4A,3 9.9, 4-H A ), 2.19 (1H, dd, J 4A,4B 12.9, J 4B,3 9.9, 4-H B ), 2.69-2.91 (1H, m, 3-H), 3.45 (1H, dd, J 1ЈA,1ЈB 12…”

Section: (3r5r)-(؊)-3-methyl-5-ethyl-5-hydroxymethyltetrahydrofuran-2...mentioning

confidence: 99%

Synthesis of the bis-spiroacetal moiety of the polyether antibiotic CP44,161

Allen

Brimble

Prabaharan

2001

J. Chem. Soc., Perkin Trans. 1

View full text Add to dashboard Cite

The syntheses of bis-spiroacetals 25a, 25c and 40 which constitute the central framework of the polyether antibiotic CP44,161 4, are described. The tricyclic bis-spiroacetal ring is formed by oxidative cyclisation of hydroxyspiroacetal 9 which in turn is assembled from lactone 10 and acetylene 11. The key stereogenic centres in acetylene 11 were assembled using a Sharpless asymmetric dihydroxylation and an Evans asymmetric alkylation of a chiral oxazolidinone. Asymmetric dihydroxylation of alkene 14 using (DHQ) 2 PHAL (hydroquinine phthalazine-1,4-diyl diether) led to acetylene 22 which in turn was converted to bis-spiroacetals 25a and 25c. Construction of the isomeric acetylene 11 was effected via Sharpless asymmetric dihydroxylation of alkene 14 using the pseudoenantiomeric chiral ligand (DHQD) 2 PHAL which in turn led to the formation of bis-spiroacetal 40 with the same configuration at C-2 as that present in antibiotic CP44,161 4. Barbier addition of bromide 8 to bisspiroacetal aldehyde 27 afforded alcohol 28 which was then converted to polyethers 32 and 33 via an epoxidation cyclization strategy. This latter reaction sequence demonstrated the feasibility of appending the E ring to the tricyclic bis-spiroacetal BCD ring system of antibiotic CP44,161 4.

show abstract

“…~~, ~~ A stereocontrolled total synthesis has been achieved. 61 The producing organism, Streptomyces albus ATCC 21 838, also makes a number of closely related analogues.62 Treatment of salinomycin with base (Scheme 2) led to cleavage of the cring to yield the y-lactone, (20).63 A thermal retro-aldol reaction cleaved the C-9,ll /3-hydroxy ketone. 64 The 20-hydroxyl group was selectively acylated using acid anhydride (Scheme 2) and pyridine and the 11-ketone was reduced using sodium borohydride.…”

Section: Salinomycinmentioning

confidence: 99%

Polyether ionophores

Dutton¹,

Banks²,

COOPER³

1995

Nat. Prod. Rep.

155

107

View full text Add to dashboard Cite

TM-582CP-78 545 chelate metal ions selectively. These uses have maintained the X-206X-206 (7), also known as antibiotic C41 or 6-desmethylalborixin, was one of the first polyether ionophores to be discovered, but there was a delay of some years before its structure was e1~cidated.l~ It was isolated from a fermentation of Streptomyces X-206.20 Degradation studies showed that the A-ring of the antibiotic was a C-3 epimer of the corresponding ring in nigericin (70) (vide infra). The antibiotic has been prepared by total synthesis.

show abstract

Highly stereocontrolled total synthesis of the polyether antibiotic salinomycin. III. Total synthesis of salinomycin via coupling of C1-C9, C10-C17, and C-18-C30 segments.

Cited by 22 publications

References 0 publications

Comprehensive Study of Okaspirodiol: Characterization, Total Synthesis, and Biosynthesis of a New Metabolite fromStreptomyces

Comprehensive Study of Okaspirodiol: Characterization, Total Synthesis, and Biosynthesis of a New Metabolite fromStreptomyces

Synthesis of the bis-spiroacetal moiety of the polyether antibiotic CP44,161

Polyether ionophores

Contact Info

Product

Resources

About