Enantioselective Modular Total Synthesis of Macrolides Sch725674 and C‐4‐<i>epi</i>‐Sch725674

Sharma, Brijesh M.; Gontala, Arjun; Kumar, Pradeep

doi:10.1002/ejoc.201501531

Cited by 14 publications

(2 citation statements)

References 31 publications

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“…16 Aldehyde 12 17 was efficiently obtained by protection of homoallylic alcohol 11 and Lemieux−Johnson oxidative cleavage of 8. 18 The synthesis of the protected anti-1,3-diol used a diastereoselective Krische's allylation reaction 13 of 12 but with (R)-BINAP and at lower temperature (100 °C), which provided homoallylic alcohol 13 in 70 yield. Diastereoselectivity was determined by 1 H NMR analysis of the cyclic acetals generated after deprotection of 13 (see S.I.).…”

Section: Resultsmentioning

confidence: 99%

From Acyclic Intramolecular-[4 + 2]- to Transannular Bis-[4 + 2]-Cycloaddition of the Macrodiolide for the Stereoselective Synthesis of the Octahydronaphthalene Core of Polyenic Macrolactam Sagamilactam

Iglesias-Menduiña,

Novegil,

Martínez

et al. 2024

Org. Lett.

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The strategy for the synthesis of the octahydronaphthalene core of natural macrolide sagamilactam has unintentionally evolved from the acyclic intramolecular (IMDA) to the transannular (TADA) Diels−Alder reaction. Lewis acid-promoted IMDA of a protected 2Z,8E,10E-4,6,12-trihydroxy-2,8,10-decatrienal model with a diol of 4,6-anti relative configuration, as proposed by DP4+-based computational studies, afforded the cis-octahydronaphthalene diastereomer through the Re-endo approach. The 26-membered macrodiolide generated, under thermal reaction conditions, the trans-octahydronaphthalene by a double TADA reaction along the desired Si-exo orientation.

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Section: Resultsmentioning

confidence: 99%

From Acyclic Intramolecular-[4 + 2]- to Transannular Bis-[4 + 2]-Cycloaddition of the Macrodiolide for the Stereoselective Synthesis of the Octahydronaphthalene Core of Polyenic Macrolactam Sagamilactam

Iglesias-Menduiña,

Novegil,

Martínez

et al. 2024

Org. Lett.

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“…The synthesis of hydroxy olefins 4e – 4h is depicted in Scheme C. Regioselective ring opening of epoxide 14 with propargyl Grignard reagent (propargyl bromide, Mg, HgCl 2 ) gave bis-homopropargylic alcohol 15 , which was silylated with TBSCl/imidazole to deliver silyl ether 16 . Carreira asymmetric alkynylation of cyclohexanecarboxaldehyde with 16 in the presence of (+)- N -methylephedrine (NME) or its enantiomer (Zn(OTf) 2 , Et 3 N, toluene) led to propargylic alcohol 17a (84%) or 17b (86%), with greater than 20:1 diastereoselectivity in each case.…”

Section: Results and Discussionmentioning

confidence: 99%

Cobalt-Catalyzed Hartung–Mukaiyama Cyclization of γ-Hydroxy Olefins: Stereocontrolled Synthesis of the Tetrahydrofuran Moiety of Amphidinolide N

et al. 2021

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Cobalt-catalyzed Mukaiyama-type cyclization of γ-hydroxy olefins is known as an atom-and step-economical means for stereoselective synthesis of 2,5-trans-substituted tetrahydrofuran derivatives. In this study, we investigated the synthesis of a series of 2,5-substituted tetrahydrofuran derivatives by means of a cobalt-catalyzed Hartung−Mukaiyama cyclization. The stereochemical consequence of the reaction was found to be largely dependent on the substitution pattern and relative configuration of γ-hydroxy olefins. 2,5-cis-Substituted tetrahydrofuran derivatives could be obtained diastereoselectively from appropriately substituted γ-hydroxy olefins. Additionally, relatively bulky olefin substituents and unprotected hydroxy groups at non-interfering positions (e.g., α and δ) were well tolerated in the reaction. Finally, the synthetic versatility of the Hartung−Mukaiyama cyclization was demonstrated through a stereocontrolled synthesis of the tetrahydrofuran moiety of amphidinolide N, a potent cytotoxic macrolide of marine origin. This study expands the capacity of Mukaiyama-type cyclization in that it can be used in convergent assembly of complex tetrahydrofuran motifs from internal olefins.

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Regio‐ and Stereoselective Homologation of 1,2‐Bis(Boronic Esters): Stereocontrolled Synthesis of 1,3‐Diols and Sch 725674

et al. 2016

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1,2-Bis(boronic esters), derived from the enantioselective diboration of terminal alkenes,c an be selectively homologated at the primary boronic ester by using enantioenriched primary/secondary lithiated carbamates or benzoates to give 1,3-bis(boronic esters), which can be subsequently oxidized to the corresponding secondary-secondary and secondary-tertiary 1,3-diols with full stereocontrol. The transformation was applied to ac oncise total synthesis of the 14membered macrolactone,S ch 725674. The nine-step synthetic route also features an ovel desymmetrizing enantioselective diboration of ad ivinyl carbinol derivative and high-yielding late-stage cross-metathesis and Yamaguchi macrolactonization reactions.Scheme 1. Homologation of organoboron compounds.

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Enantioselective Modular Total Synthesis of Macrolides Sch725674 and C‐4‐epi‐Sch725674

Cited by 14 publications

References 31 publications

From Acyclic Intramolecular-[4 + 2]- to Transannular Bis-[4 + 2]-Cycloaddition of the Macrodiolide for the Stereoselective Synthesis of the Octahydronaphthalene Core of Polyenic Macrolactam Sagamilactam

From Acyclic Intramolecular-[4 + 2]- to Transannular Bis-[4 + 2]-Cycloaddition of the Macrodiolide for the Stereoselective Synthesis of the Octahydronaphthalene Core of Polyenic Macrolactam Sagamilactam

Cobalt-Catalyzed Hartung–Mukaiyama Cyclization of γ-Hydroxy Olefins: Stereocontrolled Synthesis of the Tetrahydrofuran Moiety of Amphidinolide N

Regio‐ and Stereoselective Homologation of 1,2‐Bis(Boronic Esters): Stereocontrolled Synthesis of 1,3‐Diols and Sch 725674

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