Stereocontrolled Synthesis of a Key Lactone Intermediate Required for the Synthesis of Salinomycin

Brimble, Margaret

doi:10.1071/ch9901035

Cited by 17 publications

(5 citation statements)

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“…Aldol reaction of 587 with N -butanoyl oxazolidinethione 588 catalyzed by Sn(OTf) 2 , using conditions developed by Nagao afforded aldol adduct 589 in 91% yield. Reductive removal of the auxiliary, followed by lactone formation, completed the synthesis of the C 11 −C 17 fragment 574 in 12 steps and 15% overall yield 128 …”

Section: Synthesis Of the C 11 −C 17 Fragmentmentioning

confidence: 99%

Strategy and Methodology Development for the Total Synthesis of Polyether Ionophore Antibiotics

2000

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Section: Synthesis Of the C 11 −C 17 Fragmentmentioning

confidence: 99%

Strategy and Methodology Development for the Total Synthesis of Polyether Ionophore Antibiotics

2000

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“…To a solution of diisopropylamine (1.06 g, 10.5 mmol) in dry tetrahydrofuran (25 ml), cooled to 0 ЊC under nitrogen, was added n-butyllithium (6.4 ml of a 1.5 M solution in hexane, 9.62 mmol). After stirring at 0 ЊC for 15 min, the reaction mixture was cooled to Ϫ78 ЊC, whereupon a solution of (4S,5R)-(Ϫ)-4methyl-3-(1Ј-oxopropyl)-5-phenyloxazolidin-2-one 28, 29 (2.04 g, 8.75 mmol) in dry tetrahydrofuran (10 ml) was added. After stirring at Ϫ78 ЊC for 20 min, a solution of freshly distilled iodide 13 (3.43 g, 17.5 mmol) in dry tetrahydrofuran (10 ml) was added dropwise.…”

Section: -(Iodomethyl)but-1-ene 13mentioning

confidence: 99%

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

Allen

Brimble

Prabaharan

2001

J. Chem. Soc., Perkin Trans. 1

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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.

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“…An Evans aldol reaction [47] between 102 and the chiral N-butyroyloxazolidinone 103 [48] stereoselectively provided the syn adduct in an excellent yield of 89 %. Protection of the primary alcohol in 101 and hydride reduction of the ester followed by Swern oxidation provided aldehyde 102.…”

Section: Total Synthesis Of (-)-Spiculoic Acid a By The Baldwin/ Lee mentioning

confidence: 99%

“…Protection of the primary alcohol in 101 and hydride reduction of the ester followed by Swern oxidation provided aldehyde 102. An Evans aldol reaction [47] between 102 and the chiral N-butyroyloxazolidinone 103 [48] stereoselectively provided the syn adduct in an excellent yield of 89 %. LiBH 4 -mediated removal [49] of the auxiliary from 104 provided the diol 105.…”

Section: Total Synthesis Of (-)-Spiculoic Acid a By The Baldwin/ Lee mentioning

confidence: 99%

Natural Product Synthesis Featuring Intramolecular Diels–Alder Approaches – Total Syntheses of Tubelactomicins and Spiculoic Acid A

Tadano

2009

Eur J Org Chem

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We have recently accomplished the total syntheses of the antimicrobial tricyclic 16‐membered macrolides (+)‐tubelactomicin A, B, D, and E by common synthetic approaches based on intramolecular Diels–Alder (IMDA) reactions. These total syntheses established the relative and absolute configurations of three antibiotics – (+)‐tubelactomicins B, D, and E – for which only planar structures had been previously reported. In addition, we have very recently accomplished the total synthesis of a marine natural product, (+)‐spiculoic acid A, by an IMDA strategy. This Microreview summarizes our total syntheses of the four tubelactomicns and the total synthesis of (+)‐tubelactomicin A by Tatsuta et al. Both approaches were based on the use of stereoselective IMDA reactions for the construction of the lower‐half segments of the antibiotics. Total syntheses of the unnatural (–) and natural (+) enantiomers of spiculoic acid A, the former achieved by Baldwin and Lee's group and the latter achieved by the author's group, are also summarized. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Stereocontrolled Synthesis of a Key Lactone Intermediate Required for the Synthesis of Salinomycin

Abstract: The stereocontrolled synthesis of lactone (1b), a key intermediate required for the synthesis of the polyether antibiotic salinomycin, is described.

Cited by 17 publications

References 0 publications

Strategy and Methodology Development for the Total Synthesis of Polyether Ionophore Antibiotics

Strategy and Methodology Development for the Total Synthesis of Polyether Ionophore Antibiotics

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

Natural Product Synthesis Featuring Intramolecular Diels–Alder Approaches – Total Syntheses of Tubelactomicins and Spiculoic Acid A

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